DNA-PK inhibitors

ABSTRACT

A compound of formula I: 
                         
and isomers, salts, solvates, chemically protected forms, and prodrugs thereof, wherein: R 1  and R 2  are independently selected from hydrogen, an optionally substituted C 1-7  alkyl group, C 3-20  heterocyclyl group, or C 5-20  aryl group, or may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms; Q is —NH—C(═O)— or —O—; Y is an optionally substituted C 1-5  alkylene group; X is selected from SR 3  or NR 4 R 5 , wherein, R 3 , or R 4  and R 5  are independently selected from hydrogen, optionally substituted C 1-7  alkyl, C 5-20  aryl, or C 3-20  heterocyclyl groups, or R 4  and R 5  may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms; if Q is —O—, X is additionally selected from —C(═O)—NR 6 R 7 , wherein R 6  and R 7  are independently selected from hydrogen, optionally substituted C 1-7  alkyl, C 5-20  aryl, or C 3-20  heterocyclyl groups, or R 6  and R 7  may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms; and if Q is —NH—C(═O)—, —Y—X may additionally be selected from C 1-7  alkyl.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 11/231,041, filed on Sep. 20, 2005, which claims the priority benefits of U.S. Provisional Application No. 60/611,515, filed on Sep. 20, 2004, and which are both incorporated herein by reference.

The present invention relates to compounds which act as DNA-PK inhibitors, their use and synthesis.

The DNA-dependent protein kinase (DNA-PK) is a nuclear serine/threonine protein kinase that is activated upon association with DNA. Biochemical and genetic data have revealed this kinase to be composed of a large catalytic subunit, termed DNA-PKcs, and a regulatory component termed Ku. DNA-PK has been shown to be a crucial component of both the DNA double-strand break (DSB) repair machinery and the V(D)J recombination apparatus. In addition, recent work has implicated DNA-PK components in a variety of other processes, including the modulation of chromatin structure and telomere maintenance (Smith, G. C. M. and Jackson, S. P., Genes and Dev. 13: 916-934 (1999)).

DNA DSBs are regarded as the most lethal lesion a cell can encounter. To combat the serious threats posed by DNA DSBs, eukaryotic cells have evolved several mechanisms to mediate their repair. In higher eukaryotes, the predominant of these mechanisms is DNA non-homologous end-joining (NHEJ), also known as illegitimate recombination. DNA-PK plays a key role in this pathway. Increased DNA-PK activity has been demonstrated both in vitro and in vivo and correlates with the resistance of tumour cells IR and bifunctional alkylating agents (Muller C., et al., Blood, 92, 2213-2219 (1998), Sirzen F., et al., Eur. J. Cancer, 35, 111-116 (1999)). Therefore, increased DNA-PK activity has been proposed as a cellular and tumour resistance mechanism. Hence, inhibition of DNA-PK with a small molecule inhibitor may prove efficacious in tumours where over-expression is regarded as a resistance mechanism.

It also has been previously found that the PI 3-kinase inhibitor LY294002:

is able to inhibit DNA-PK function in vitro (Izzard, R. A., et al., Cancer Res. 59: 2581-2586 (1999)). The IC₅₀ (concentration at which 50% of enzyme activity is lost) for LY294002 towards DNA-PK is, at ˜1 μM, the same as that for PI 3-kinase. Furthermore it has been shown that LY294002 is also able to weakly sensitise cells to the effects of IR (Rosenzweig, K. E., et al., Clin. Cancer Res. 3: 1149-1156 (1999)).

WO 03/024949 describes a number of classes of compounds useful as DNA-PK inhibitors, including 2-amino-chromen-4-ones of the general structure:

of which:

was one example. This compound exhibited an IC₅₀ of 10-12 nM and an SER of 1.3 (see below for methods).

Other examples of a DNA-PK inhibitors include 1(2-hydroxy-4-morpholin-4-yl-phenyl)-ethanone (Kashishian, A., et al., Mol. Cancer Ther, 2, 1257-1264 (2003))):

and SU11752 (Ismail, I. H., et al., Oncogene, 23, 873-882 (2004))

Given the involvement of DNA-PK in DNA repair processes, and that small molecule inhibitors have been shown to radio- and chemo-sensitise mammalian cells in culture, an application of specific DNA-PK inhibitory drugs would be to act as agents that will enhance the efficacy of both cancer chemotherapy and radiotherapy. DNA-PK inhibitors may also prove useful in the treatment of retroviral mediated diseases. For example it has been demonstrated that loss of DNA-PK activity severely represses the process of retroviral integration (Daniel R, et al., Science, 284:644-7 (1999)).

The present inventors have now discovered related compounds which exhibit similar or improved levels of DNA-PK inhibition, whilst possessing other useful properties for use as active pharmaceuticals, in particular improved solubility.

Accordingly, the first aspect of the invention provides a compound of formula I:

and isomers, salts, solvates, chemically protected forms, and prodrugs thereof, wherein: R¹ and R² are independently selected from hydrogen, an optionally substituted C₁₋₇ alkyl group, C₃₋₂₀ heterocyclyl group, or C₅₋₂₀ aryl group, or may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms; Q is —NH—C(═O)— or —O—; Y is an optionally substituted C₁₋₅ alkylene group; X is selected from SR³ or NR⁴R⁵, wherein, R³, or R⁴ and R⁵ are independently selected from hydrogen, optionally substituted C₁₋₇ alkyl, C₅₋₂₀ aryl, or C₃₋₂₀ heterocyclyl groups, or R⁴ and R⁵ may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms; if Q is —O—, X is additionally selected from —C(═O)—NR⁶R⁷, wherein R⁶ and R⁷ are independently selected from hydrogen, optionally substituted C₁₋₇ alkyl, C₅₋₂₀ aryl, or C₃₋₂₀ heterocyclyl groups, or R⁶ and R⁷ may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms; and if Q is —NH—C(═O)—, —Y—X may additionally selected from C₁₋₇ alkyl.

A second aspect of the invention provides a composition comprising a compound of the first aspect and a pharmaceutically acceptable carrier or diluent.

A third aspect of the invention provides a compound of the first aspect for use in a method of therapy.

A fourth aspect of the invention provides for the use of a compound of the first aspect in the preparation of a medicament for treating a disease ameliorated by the inhibition of DNA-PK.

It is preferred that the medicament of the fourth aspect selectivity inhibits the activity of DNA-PK compared to PI 3-kinase and/or ATM. Selectivity is an important issue as inhibition of other PI 3-kinase family members may lead to unwanted side-effects associated with the loss of function of those enzymes.

In particular, the compounds may be used in the preparation of a medicament for:

(a) use as an adjunct in cancer therapy or for potentiating tumour cells for treatment with ionising radiation or chemotherapeutic agents; or

(b) the treatment of retroviral mediated diseases.

A further aspect of the invention provides an active compound as described herein for use in a method of treatment of the human or animal body, preferably in the form of a pharmaceutical composition.

Another aspect of the invention provides a method of inhibiting DNA-PK in vitro or in vivo, comprising contacting a cell with an effective amount of an active compound as described herein.

DEFINITIONS

C₁₋₇ alkyl: The term “C₁₋₇ alkyl”, as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a C₁₋₇ hydrocarbon compound having from 1 to 7 carbon atoms, which may be aliphatic or alicyclic, or a combination thereof, and which may be saturated, partially unsaturated, or fully unsaturated.

Examples of saturated linear C₁₋₇ alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, and n-pentyl (amyl).

Examples of saturated branched C₁₋₇ alkyl groups include, but are not limited to, iso-propyl, iso-butyl, sec-butyl, tert-butyl, and neo-pentyl.

Examples of saturated alicyclic C₁₋₇ alkyl groups (also referred to as “C₃₋₇ cycloalkyl” groups) include, but are not limited to, groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl, as well as substituted groups (e.g., groups which comprise such groups), such as methylcyclopropyl, dimethylcyclopropyl, methylcyclobutyl, dimethylcyclobutyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, cyclopropylmethyl and cyclohexylmethyl.

Examples of unsaturated C₁₋₇ alkyl groups which have one or more carbon-carbon double bonds (also referred to as “C₂₋₇alkenyl” groups) include, but are not limited to, ethenyl (vinyl, —CH═CH₂), 2-propenyl (allyl, —CH—CH═CH₂), isopropenyl (—C(CH₃)═CH₂), butenyl, pentenyl, and hexenyl.

Examples of unsaturated C₁₋₇ alkyl groups which have one or more carbon-carbon triple bonds (also referred to as “C₂₋₇ alkynyl” groups) include, but are not limited to, ethynyl (ethinyl) and 2-propynyl (propargyl).

Examples of unsaturated alicyclic (carbocyclic) C₁₋₇ alkyl groups which have one or more carbon-carbon double bonds (also referred to as “C₃₋₇cycloalkenyl” groups) include, but are not limited to, unsubstituted groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl, as well as substituted groups (e.g., groups which comprise such groups) such as cyclopropenylmethyl and cyclohexenylmethyl.

C₃₋₂₀ heterocyclyl: The term “C₃₋₂₀ heterocyclyl”, as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a ring atom of a C₃₋₂₀ heterocyclic compound, said compound having one ring, or two or more rings (e.g., spiro, fused, bridged), and having from 3 to 20 ring atoms, atoms, of which from 1 to 10 are ring heteroatoms, and wherein at least one of said ring(s) is a heterocyclic ring. Preferably, each ring has from 3 to 7 ring atoms, of which from 1 to 4 are ring heteroatoms. “C₃₋₂₀” denotes ring atoms, whether carbon atoms or heteroatoms.

Examples of C₃₋₂₀ heterocyclyl groups having one nitrogen ring atom include, but are not limited to, those derived from aziridine, azetidine, pyrrolidines (tetrahydropyrrole), pyrroline (e.g., 3-pyrroline, 2,5-dihydropyrrole), 2H-pyrrole or 3H-pyrrole (isopyrrole, isoazole), piperidine, dihydropyridine, tetrahydropyridine, and azepine.

Examples of C₃₋₂₀ heterocyclyl groups having one oxygen ring atom include, but are not limited to, those derived from oxirane, oxetane, oxolane (tetrahydrofuran), oxole (dihydrofuran), oxane (tetrahydropyran), dihydropyran, pyran (C₆), and oxepin. Examples of substituted C₃₋₂₀ heterocyclyl groups include sugars, in cyclic form, for example, furanoses and pyranoses, including, for example, ribose, lyxose, xylose, galactose, sucrose, fructose, and arabinose.

Examples of C₃₋₂₀ heterocyclyl groups having one sulphur ring atom include, but are not limited to, those derived from thiirane, thietane, thiolane (tetrahydrothiophene), thiane (tetrahydrothiopyran), and thiepane.

Examples of C₃₋₂₀ heterocyclyl groups having two oxygen ring atoms include, but are not limited to, those derived from dioxolane, dioxane, and dioxepane.

Examples of C₃₋₂₀ heterocyclyl groups having two nitrogen ring atoms include, but are not limited to, those derived from imidazolidine, pyrazolidine (diazolidine), imidazoline, pyrazoline (dihydropyrazole), and piperazine.

Examples of C₃₋₂₀ heterocyclyl groups having one nitrogen ring atom and one oxygen ring atom include, but are not limited to, those derived from tetrahydrooxazole, dihydrooxazole, tetrahydroisoxazole, dihydroisoxazole, morpholine, tetrahydrooxazine, dihydrooxazine, and oxazine.

Examples of C₃₋₂₀ heterocyclyl groups having one oxygen ring atom and one sulphur ring atom include, but are not limited to, those derived from oxathiolane and oxathiane (thioxane).

Examples of C₃₋₂₀ heterocyclyl groups having one nitrogen ring atom and one sulphur ring atom include, but are not limited to, those derived from thiazoline, thiazolidine, and thiomorpholine.

Other examples of C₃₋₂₀heterocyclyl groups include, but are not limited to, oxadiazine and oxathiazine.

Examples of heterocyclyl groups which additionally bear one or more oxo (═O) groups, include, but are not limited to, those derived from:

C₅ heterocyclics, such as furanone, pyrone, pyrrolidone (pyrrolidinone), pyrazolone (pyrazolinone), imidazolidone, thiazolone, and isothiazolone;

C₆ heterocyclics, such as piperidinone (piperidone), piperidinedione, piperazinone, piperazinedione, pyridazinone, and pyrimidinone (e.g., cytosine, thymine, uracil), and barbituric acid;

fused heterocyclics, such as oxindole, purinone (e.g., guanine), benzoxazolinone, benzopyrone (e.g., coumarin);

cyclic anhydrides (—C(═O)—O—C(═O)— in a ring), including but not limited to maleic anhydride, succinic anhydride, and glutaric anhydride;

cyclic carbonates (—O—C(═O)—O— in a ring), such as ethylene carbonate and 1,2-propylene carbonate;

imides (—C(═O)—NR—C(═O)— in a ring), including but not limited to, succinimide, maleimide, phthalimide, and glutarimide;

lactones (cyclic esters, —O—C(═O)— in a ring), including, but not limited to, β-propiolactone, γ-butyrolactone, δ-valerolactone (2-piperidone), and ε-caprolactone;

lactams (cyclic amides, —NR—C(═O)— in a ring), including, but not limited to, β-propiolactam, γ-butyrolactam (2-pyrrolidone), δ-valerolactam, and ε-caprolactam;

cyclic carbamates (—O—C(═O)—NR— in a ring), such as 2-oxazolidone;

cyclic ureas (—NR—C(═O)—NR— in a ring), such as 2-imidazolidone and pyrimidine-2,4-dione (e.g., thymine, uracil).

C₅₋₂₀ aryl: The term “C₅₋₂₀ aryl”, as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from an aromatic ring atom of a C₅₋₂₀ aromatic compound, said compound having one ring, or two or more rings (e.g., fused), and having from 5 to 20 ring atoms, and wherein at least one of said ring(s) is an aromatic ring. Preferably, each ring has from 5 to 7 ring atoms.

The ring atoms may be all carbon atoms, as in “carboaryl groups”, in which case the group may conveniently be referred to as a “C₅₋₂₀ carboaryl” group.

Examples of C₅₋₂₀ aryl groups which do not have ring heteroatoms (i.e. C₅₋₂₀ carboaryl groups) include, but are not limited to, those derived from benzene (i.e. phenyl) (C₆), naphthalene (C₁₀), anthracene (C₁₄), phenanthrene (C₁₄), naphthacene (C₁₈), and pyrene (C₁₆).

Examples of aryl groups which comprise fused rings, one of which is not an aromatic ring, include, but are not limited to, groups derived from indene and fluorene.

Alternatively, the ring atoms may include one or more heteroatoms, including but not limited to oxygen, nitrogen, and sulphur, as in “heteroaryl groups”. In this case, the group may conveniently be referred to as a “C₅₋₂₀ heteroaryl” group, wherein “C₅₋₂₀” denotes ring atoms, whether carbon atoms or heteroatoms. Preferably, each ring has from 5 to 7 ring atoms, of which from 0 to 4 are ring heteroatoms.

Examples of C₅₋₂₀ heteroaryl groups include, but are not limited to, C₅ heteroaryl groups derived from furan (oxole), thiophene (thiole), pyrrole (azole), imidazole (1,3-diazole), pyrazole (1,2-diazole), triazole, oxazole, isoxazole, thiazole, isothiazole, oxadiazole, and oxatriazole; and C₆ heteroaryl groups derived from isoxazine, pyridine (azine), pyridazine (1,2-diazine), pyrimidine (1,3-diazine; e.g., cytosine, thymine, uracil), pyrazine (1,4-diazine), triazine, tetrazole, and oxadiazole (furazan).

Examples of C₅₋₂₀ heterocyclic groups (some of which are C₅₋₂₀ heteroaryl groups) which comprise fused rings, include, but are not limited to, C₉ heterocyclic groups derived from benzofuran, isobenzofuran, indole, isoindole, purine (e.g., adenine, guanine), benzothiophene, benzimidazole; C₁₀ heterocyclic groups derived from quinoline, isoquinoline, benzodiazine, pyridopyridine, quinoxaline; C₁₃ heterocyclic groups derived from carbazole, dibenzothiophene, dibenzofuran; C₁₄ heterocyclic groups derived from acridine, xanthene, phenoxathiin, phenazine, phenoxazine, phenothiazine.

The above C₁₋₇ alkyl, C₃₋₂₀ heterocyclyl and C₅₋₂₀ aryl groups whether alone or part of another substituent, may themselves optionally be substituted with one or more groups selected from themselves and the additional substituents listed below.

Halo: —F, —Cl, —Br, and —I.

Hydroxy: —OH.

Ether: —OR, wherein R is an ether substituent, for example, a C₁₋₇ alkyl group (also referred to as a C₁₋₇ alkoxy group, discussed below), a C₃₋₂₀ heterocyclyl group (also referred to as a C₃₋₂₀ heterocyclyloxy group), or a C₅₋₂₀ aryl group (also referred to as a C₅₋₂₀ aryloxy group), preferably a C₁₋₇ alkyl group.

C₁₋₇ alkoxy: —OR, wherein R is a C₁₋₇ alkyl group. Examples of C₁₋₇ alkoxy groups include, but are not limited to, —OCH₃ (methoxy), —OCH₂CH₃ (ethoxy) and —OC(CH₃)₃ (tert-butoxy).

Oxo (keto, -one): ═O. Examples of cyclic compounds and/or groups having, as a substituent, an oxo group (═O) include, but are not limited to, carbocyclics such as cyclopentanone and cyclohexanone; heterocyclics, such as pyrone, pyrrolidone, pyrazolone, pyrazolinone, piperidone, piperidinedione, piperazinedione, and imidazolidone; cyclic anhydrides, including but not limited to maleic anhydride and succinic anhydride; cyclic carbonates, such as propylene carbonate; imides, including but not limited to, succinimide and maleimide; lactones (cyclic esters, —O—C(═O)— in a ring), including, but not limited to, β-propiolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone; and lactams (cyclic amides, —NH—C(═O)— in a ring), including, but not limited to, β-propiolactam, γ-butyrolactam (2-pyrrolidone), δ-valerolactam, and ε-caprolactam.

Imino (imine): ═NR, wherein R is an imino substituent, for example, hydrogen, C₁₋₇alkyl group, a C₃₋₂₀heterocyclyl group, or a C₅₋₂₀ aryl group, preferably hydrogen or a C₁₋₇ alkyl group. Examples of ester groups include, but are not limited to, ═NH, ═NMe, ═NEt, and ═NPh.

Formyl (carbaldehyde, carboxaldehyde): —C(═O)H.

Acyl (keto): —C(═O)R, wherein R is an acyl substituent, for example, a C₁₋₇alkyl group (also referred to as C₁₋₇ alkylacyl or C₁₋₇ alkanoyl), a C₃₋₂₀ heterocyclyl group (also referred to as C₃₋₂₀ heterocyclylacyl), or a C₅₋₂₀ aryl group (also referred to as C₅₋₂₀ arylacyl), preferably a C₁₋₇ alkyl group. Examples of acyl groups include, but are not limited to, —C(═O)CH₃ (acetyl), —C(═O)CH₂CH₃ (propionyl), —C(═O)C(CH₃)₃ (butyryl), and —C(═O)Ph (benzoyl, phenone).

Carboxy (carboxylic acid): —COOH.

Ester (carboxylate, carboxylic acid ester, oxycarbonyl): —C(═O)OR, wherein R is an ester substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇alkyl group. Examples of ester groups include, but are not limited to, —C(═O)OCH₃, —C(═O)OCH₂CH₃, —C(═O)OC(CH₃)₃, and —C(═O)OPh.

Acyloxy (reverse ester): —OC(═O)R, wherein R is an acyloxy substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇alkyl group. Examples of acyloxy groups include, but are not limited to, —OC(═O)CH₃ (acetoxy), —OC(═O)CH₂CH₃, —OC(═O)C(CH₃)₃, —OC(═O)Ph, and —OC(═O)CH₂Ph.

Amido (carbamoyl, carbamyl, aminocarbonyl, carboxamide): —C(═O)NR¹R², wherein R¹ and R² are independently amino substituents, as defined for amino groups. Examples of amido groups include, but are not limited to, —C(═O)NH₂, —C(═O)NHCH₃, —C(═O)N(CH₃)₂, —C(═O)NHCH₂CH₃, and —C(═O)N(CH₂CH₃)₂, as well as amido groups in which R¹ and R², together with the nitrogen atom to which they are attached, form a heterocyclic structure as in, for example, piperidinocarbonyl, morpholinocarbonyl, thiomorpholinocarbonyl, and piperazinocarbonyl.

Acylamido (acylamino): —NR¹C(═O)R², wherein R¹ is an amide substituent, for example, hydrogen, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably hydrogen or a C₁₋₇ alkyl group, and R² is an acyl substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably hydrogen or a C₁₋₇ alkyl group. Examples of acylamide groups include, but are not limited to, —NHC(═O)CH₃, —NHC(═O)CH₂CH₃, and —NHC(═O)Ph. R¹ and R² may together form a cyclic structure, as in, for example, succinimidyl, maleimidyl and phthalimidyl:

Acylureido: —N(R¹)C(O)NR²C(O)R³ wherein R¹ and R² are independently ureido substituents, for example, hydrogen, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably hydrogen or a C₁₋₇ alkyl group. R³ is an acyl group as defined for acyl groups. Examples of acylureido groups include, but are not limited to, —NHCONHC(O)H, —NHCONMeC(O)H, —NHCONEtC(O)H, —NHCONMeC(O)Me, —NHCONEtC(O)Et, —NMeCONHC(O)Et, —NMeCONHC(O)Me, —NMeCONHC(O)Et, —NMeCONMeC(O)Me, —NMeCONEtC(O)Et, and —NMeCONHC(O)Ph.

Carbamate: —NR¹—C(O)—OR² wherein R¹ is an amino substituent as defined for amino groups and R² is an ester group as defined for ester groups. Examples of carbamate groups include, but are not limited to, —NH—C(O)—O-Me, —NMe-C(O)—O-Me, —NH—C(O)—O-Et, —NMe-C(O)—O-t-butyl, and —NH—C(O)—O-Ph.

Thioamido (thiocarbamyl): —C(═S)NR¹R², wherein R¹ and R² are independently amino substituents, as defined for amino groups. Examples of amido groups include, but are not limited to, —C(═S)NH₂, —C(═S)NHCH₃, —C(═S)N(CH₃)₂, and —C(═S)NHCH₂CH₃.

Tetrazolyl: a five membered aromatic ring having four nitrogen atoms and one carbon atom,

Amino: —NR¹R², wherein R¹ and R² are independently amino substituents, for example, hydrogen, a C₁₋₇ alkyl group (also referred to as C₁₋₇ alkylamino or di-C₁₋₇ alkylamino), a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably H or a C₁₋₇alkyl group, or, in the case of a “cyclic” amino group, R¹ and R², taken together with the nitrogen atom to which they are attached, form a heterocyclic ring having from 4 to 8 ring atoms. Examples of amino groups include, but are not limited to, —NH₂, —NHCH₃, —NHC(CH₃)₂, —N(CH₃)₂, —N(CH₂CH₃)₂, and —NHPh. Examples of cyclic amino groups include, but are not limited to, aziridino, azetidino, pyrrolidino, piperidino, piperazino, morpholino, and thiomorpholino.

Imino: ═NR, wherein R is an imino substituent, for example, hydrogen, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably H or a C₁₋₇ alkyl group.

Amidine: —C(═NR)NR₂, wherein each R is an amidine substituent, for example, hydrogen, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably H or a C₁₋₇ alkyl group. An example of an amidine group is —C(═NH)NH₂.

Carbazoyl (hydrazinocarbonyl): —C(O)—NN—R¹ wherein R¹ is an amino substituent as defined for amino groups. Examples of azino groups include, but are not limited to, —C(O)—NN—H, —C(O)—NN-Me, —C(O)—NN-Et, —C(O)—NN-Ph, and —C(O)—NN—CH₂-Ph.

Nitro: —NO₂.

Nitroso: —NO.

Azido: —N₃.

Cyano (nitrile, carbonitrile): —CN.

Isocyano: —NC.

Cyanato: —OCN.

Isocyanato: —NCO.

Thiocyano (thiocyanato): —SCN.

Isothiocyano (isothiocyanato): —NCS.

Sulfhydryl (thiol, mercapto): —SH.

Thioether (sulfide): —SR, wherein R is a thioether substituent, for example, a C₁₋₇ alkyl group (also referred to as a C₁₋₇ alkylthio group), a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group. Examples of C₁₋₇ alkylthio groups include, but are not limited to, —SCH₃ and —SCH₂CH₃.

Disulfide: —SS—R, wherein R is a disulfide substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group (also referred to herein as C₁₋₇ alkyl disulfide). Examples of C₁₋₇ alkyl disulfide groups include, but are not limited to, —SSCH₃ and —SSCH₂CH₃.

Sulfone (sulfonyl): —S(═O)₂R, wherein R is a sulfone substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group. Examples of sulfone groups include, but are not limited to, —S(═O)₂CH₃ (methanesulfonyl, mesyl), —S(═O)₂CF₃ (triflyl), —S(═O)₂CH₂CH₃, —S(═O)₂C₄F₉ (nonaflyl), —S(═O)₂CH₂CF₃ (tresyl), —S(═O)₂Ph (phenylsulfonyl), 4-methylphenylsulfonyl (tosyl), 4-bromophenylsulfonyl (brosyl), and 4-nitrophenyl (nosyl).

Sulfine (sulfinyl, sulfoxide): —S(═O)R, wherein R is a sulfine substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group. Examples of sulfine groups include, but are not limited to, —S(═O)CH₃ and —S(═O)CH₂CH₃.

Sulfonyloxy: —OS(═O)₂R, wherein R is a sulfonyloxy substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group. Examples of sulfonyloxy groups include, but are not limited to, —OS(═O)₂CH₃ and —OS(═O)₂CH₂CH₃.

Sulfinyloxy: —OS(═O)R, wherein R is a sulfinyloxy substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group. Examples of sulfinyloxy groups include, but are not limited to, —OS(═O)CH₃ and —OS(═O)CH₂CH₃.

Sulfamino: —NR¹S(═O)₂OH, wherein R¹ is an amino substituent, as defined for amino groups. Examples of sulfamino groups include, but are not limited to, —NHS(═O)₂OH and —N(CH₃)S(═O)₂OH.

Sulfonamino: —NR¹S(═O)₂R, wherein R¹ is an amino substituent, as defined for amino groups, and R is a sulfonamino substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group. Examples of sulfonamino groups include, but are not limited to, —NHS(═O)₂CH₃ and —N(CH₃)S(═O)₂C₆H₅.

Sulfinamino: —NR¹S(═O)R, wherein R¹ is an amino substituent, as defined for amino groups, and R is a sulfinamino substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group. Examples of sulfinamino groups include, but are not limited to, —NHS(═O)CH₃ and —N(CH₃)S(═O)C₆H₅.

Sulfamyl: —S(═O)NR¹R², wherein R¹ and R² are independently amino substituents, as defined for amino groups. Examples of sulfamyl groups include, but are not limited to, —S(═O)NH₂, —S(═O)NH(CH₃), —S(═O)N(CH₃)₂, —S(═O)NH(CH₂CH₃), —S(═O)N(CH₂CH₃)₂, and —S(═O)NHPh.

Sulfonamino: —NR¹S(═O)₂R, wherein R¹ is an amino substituent, as defined for amino groups, and R is a sulfonamino substituent, for example, a C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably a C₁₋₇ alkyl group. Examples of sulfonamino groups include, but are not limited to, —NHS(═O)₂CH₃ and —N(CH₃)S(═O)₂C₆H₅. A special class of sulfonamino groups are those derived from sultams—in these groups one of R¹ and R is a C₅₋₂₀ aryl group, preferably phenyl, whilst the other of R¹ and R is a bidentate group which links to the C₅₋₂₀ aryl group, such as a bidentate group derived from a C₁₋₇ alkyl group. Examples of such groups include, but are not limited to:

Phosphoramidite: —OP(OR¹)—NR² ₂, where R¹ and R² are phosphoramidite substituents, for example, —H, a (optionally substituted) C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably —H, a C₁₋₇ alkyl group, or a C₅₋₂₀ aryl group. Examples of phosphoramidite groups include, but are not limited to, —OP(OCH₂CH₃)—N(CH₃)₂, —OP(OCH₂CH₃)—N(i-Pr)₂, and —OP(OCH₂CH₂CN)—N(i-Pr)₂.

Phosphoramidate: —OP(═O)(OR¹)—NR² ₂, where R¹ and R² are phosphoramidate substituents, for example, —H, a (optionally substituted) C₁₋₇ alkyl group, a C₃₋₂₀ heterocyclyl group, or a C₅₋₂₀ aryl group, preferably —H, a C₁₋₇ alkyl group, or a C₅₋₂₀ aryl group. Examples of phosphoramidate groups include, but are not limited to, —OP(═O)(OCH₂CH₃)—N(CH₃)₂, —OP(═O)(OCH₂CH₃)—N(i-Pr)₂, and —OP(═O)(OCH₂CH₂CN)—N(i-Pr)₂.

In many cases, substituents may themselves be substituted. For example, a C₁₋₇ alkoxy group may be substituted with, for example, a C₁₋₇ alkyl (also referred to as a C₁₋₇ alkyl-C₁₋₇alkoxy group), for example, cyclohexylmethoxy, a C₃₋₂₀ heterocyclyl group (also referred to as a C₅₋₂₀ aryl-C₁₋₇ alkoxy group), for example phthalimidoethoxy, or a C₅₋₂₀ aryl group (also referred to as a C₅₋₂₀aryl-C₁₋₇alkoxy group), for example, benzyloxy.

C₁₋₅ Alkylene: The term “C₁₋₅ alkylene”, as used herein, pertains to a bidentate moiety obtained by removing two hydrogen atoms, either both from the same carbon atom, or one from each of two different carbon atoms, of an aliphatic linear hydrocarbon compound having from 1 to 5 carbon atoms (unless otherwise specified), which may be saturated, partially unsaturated, or fully unsaturated. Thus, the term “alkylene” includes the sub-classes alkenylene, alkynylene, etc., discussed below.

Examples of saturated C₁₋₅ alkylene groups include, but are not limited to, —(CH₂)_(n)— where n is an integer from 1 to 5, for example, —CH₂— (methylene), —CH₂CH₂— (ethylene), —CH₂CH₂CH₂— (propylene), and —CH₂CH₂CH₂CH₂— (butylene).

Examples of partially unsaturated C₁₋₅ alkylene groups include, but is not limited to, —CH═CH— (vinylene), —CH═CH—CH₂—, —CH₂—CH═CH₂—, —CH═CH—CH₂—CH₂—, —CH═CH—CH₂—CH₂—CH₂—, —CH═CH—CH═CH— and —CH═CH—CH═CH—CH₂—.

The substituent groups listed above may be substituents on an alkylene group.

Includes Other Forms

Included in the above are the well known ionic, salt, solvate, and protected forms of these substituents. For example, a reference to carboxylic acid (—COOH) also includes the anionic (carboxylate) form (—COO⁻), a salt or solvate thereof, as well as conventional protected forms. Similarly, a reference to an amino group includes the protonated form (—N⁺HR¹R²), a salt or solvate of the amino group, for example, a hydrochloride salt, as well as conventional protected forms of an amino group. Similarly, a reference to a hydroxyl group also includes the anionic form (—O⁻), a salt or solvate thereof, as well as conventional protected forms of a hydroxyl group.

Isomers, Salts, Solvates, Protected Forms, and Prodrugs

Certain compounds may exist in one or more particular geometric, optical, enantiomeric, diasteriomeric, epimeric, stereoisomeric, tautomeric, conformational, or anomeric forms, including but not limited to, cis- and trans-forms; E- and Z-forms; c-, t-, and r-forms; endo- and exo-forms; R-, S-, and meso-forms; D- and L-forms; d- and I-forms; (+) and (−) forms; keto-, enol-, and enolate-forms; syn- and anti-forms; synclinal- and anticlinal-forms; α- and β-forms; axial and equatorial forms; boat-, chair-, twist-, envelope-, and halfchair-forms; and combinations thereof, hereinafter collectively referred to as “isomers” (or “isomeric forms”).

Note that, except as discussed below for tautomeric forms, specifically excluded from the term “isomers”, as used herein, are structural (or constitutional) isomers (i.e. isomers which differ in the connections between atoms rather than merely by the position of atoms in space). For example, a reference to a methoxy group, —OCH₃, is not to be construed as a reference to its structural isomer, a hydroxymethyl group, —CH₂OH. Similarly, a reference to ortho-chlorophenyl is not to be construed as a reference to its structural isomer, meta-chlorophenyl. However, a reference to a class of structures may well include structurally isomeric forms falling within that class (e.g., C₁₋₇ alkyl includes n-propyl and iso-propyl; butyl includes n-, iso-, sec-, and tert-butyl; methoxyphenyl includes ortho-, meta-, and para-methoxyphenyl).

The above exclusion does not pertain to tautomeric forms, for example, keto-, enol-, and enolate-forms, as in, for example, the following tautomeric pairs: keto/enol (illustrated below), imine/enamine, amide/imino alcohol, amidine/amidine, nitroso/oxime, thioketone/enethiol, N-nitroso/hyroxyazo, and nitro/aci-nitro.

Note that specifically included in the term “isomer” are compounds with one or more isotopic substitutions. For example, H may be in any isotopic form, including ¹H, ²H (D), and ³H (T); C may be in any isotopic form, including ¹²C, ¹³C, and ¹⁴C; O may be in any isotopic form, including ¹⁶O and ¹⁸O; and the like.

Unless otherwise specified, a reference to a particular compound includes all such isomeric forms, including (wholly or partially) racemic and other mixtures thereof. Methods for the preparation (e.g. asymmetric synthesis) and separation (e.g., fractional crystallisation and chromatographic means) of such isomeric forms are either known in the art or are readily obtained by adapting the methods taught herein, or known methods, in a known manner.

Unless otherwise specified, a reference to a particular compound also includes ionic, salt, solvate, and protected forms of thereof, for example, as discussed below.

It may be convenient or desirable to prepare, purify, and/or handle a corresponding salt of the active compound, for example, a pharmaceutically-acceptable salt. Examples of pharmaceutically acceptable salts are discussed in Berge et al., 1977, “Pharmaceutically Acceptable Salts”, J. Pharm. Sci., Vol. 66, pp. 1-19.

For example, if the compound is anionic, or has a functional group which may be anionic (e.g., —COOH may be —COO⁻), then a salt may be formed with a suitable cation. Examples of suitable inorganic cations include, but are not limited to, alkali metal ions such as Na⁺ and K⁺, alkaline earth cations such as Ca²⁺ and Mg²⁺, and other cations such as Al³⁺. Examples of suitable organic cations include, but are not limited to, ammonium ion (i.e., NH₄ ⁺) and substituted ammonium ions (e.g., NH₃R⁺, NH₂R₂ ⁺, NHR₃ ⁺, NR₄ ⁺). Examples of some suitable substituted ammonium ions are those derived from: ethylamine, diethylamine, dicyclohexylamine, triethylamine, butylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, benzylamine, phenylbenzylamine, choline, meglumine, and tromethamine, as well as amino acids, such as lysine and arginine. An example of a common quaternary ammonium ion is N(CH₃)₄ ⁺.

If the compound is cationic, or has a functional group which may be cationic (e.g., —NH₂ may be —NH₃ ⁺), then a salt may be formed with a suitable anion. Examples of suitable inorganic anions include, but are not limited to, those derived from the following inorganic acids: hydrochloric, hydrobromic, hydroiodic, sulphuric, sulphurous, nitric, nitrous, phosphoric, and phosphorous. Examples of suitable organic anions include, but are not limited to, those derived from the following organic acids: acetic, propionic, succinic, glycolic, stearic, palmitic, lactic, malic, pamoic, tartaric, citric, gluconic, ascorbic, maleic, hydroxymaleic, phenylacetic, glutamic, aspartic, benzoic, cinnamic, pyruvic, salicyclic, sulfanilic, 2-acetyoxybenzoic, fumaric, phenylsulfonic, toluenesulfonic, methanesulfonic, ethanesulfonic, ethane disulfonic, oxalic, pantothenic, isethionic, valeric, lactobionic, and gluconic. Examples of suitable polymeric anions include, but are not limited to, those derived from the following polymeric acids: tannic acid, carboxymethyl cellulose.

It may be convenient or desirable to prepare, purify, and/or handle a corresponding solvate of the active compound. The term “solvate” is used herein in the conventional sense to refer to a complex of solute (e.g. active compound, salt of active compound) and solvent. If the solvent is water, the solvate may be conveniently referred to as a hydrate, for example, a mono-hydrate, a di-hydrate, a tri-hydrate, etc.

It may be convenient or desirable to prepare, purify, and/or handle the active compound in a chemically protected form. The term “chemically protected form”, as used herein, pertains to a compound in which one or more reactive functional groups are protected from undesirable chemical reactions, that is, are in the form of a protected or protecting group (also known as a masked or masking group or a blocked or blocking group). By protecting a reactive functional group, reactions involving other unprotected reactive functional groups can be performed, without affecting the protected group; the protecting group may be removed, usually in a subsequent step, without substantially affecting the remainder of the molecule. See, for example, Protective Groups in Organic Synthesis (T. Green and P. Wuts, Wiley, 1999).

For example, a hydroxy group may be protected as an ether (—OR) or an ester (—OC(═O)R), for example, as: a t-butyl ether; a benzyl, benzhydryl (diphenylmethyl), or trityl (triphenylmethyl)ether; a trimethylsilyl or t-butyldimethylsilyl ether; or an acetyl ester (—OC(═O)CH₃, —OAc).

For example, an aldehyde or ketone group may be protected as an acetal or ketal, respectively, in which the carbonyl group (>C═O) is converted to a diether (>C(OR)₂), by reaction with, for example, a primary alcohol. The aldehyde or ketone group is readily regenerated by hydrolysis using a large excess of water in the presence of acid.

For example, an amine group may be protected, for example, as an amide or a urethane, for example, as: a methyl amide (—NHCO—CH₃); a benzyloxy amide (—NHCO—OCH₂C₆H₅, —NH-Cbz); as a t-butoxy amide (—NHCO—OC(CH₃)₃, —NH-Boc); a 2-biphenyl-2-propoxy amide (—NHCO—OC(CH₃)₂C₆H₄C₆H₅, —NH-Bpoc), as a 9-fluorenylmethoxy amide (—NH-Fmoc), as a 6-nitroveratryloxy amide (—NH-Nvoc), as a 2-trimethylsilylethyloxy amide (—NH-Teoc), as a 2,2,2-trichloroethyloxy amide (—NH-Troc), as an allyloxy amide (—NH-Alloc), as a 2(phenylsulphonyl)ethyloxy amide (—NH-Psec); or, in suitable cases, as an N-oxide (>NO$).

For example, a carboxylic acid group may be protected as an ester for example, as: an C₁₋₇ alkyl ester (e.g. a methyl ester; a t-butyl ester); a C₁₋₇ haloalkyl ester (e.g., a C₁₋₇ trihaloalkyl ester); a triC₁₋₇ alkylsilyl-C₁₋₇ alkyl ester; or a C₅₋₂₀ aryl-C₁₋₇ alkyl ester (e.g. a benzyl ester; a nitrobenzyl ester); or as an amide, for example, as a methyl amide.

For example, a thiol group may be protected as a thioether (—SR), for example, as: a benzyl thioether; an acetamidomethyl ether (—S—CH₂NHC(═O)CH₃).

It may be convenient or desirable to prepare, purify, and/or handle the active compound in the form of a prodrug. The term “prodrug”, as used herein, pertains to a compound which, when metabolised (e.g. in vivo), yields the desired active compound. Typically, the prodrug is inactive, or less active than the active compound, but may provide advantageous handling, administration, or metabolic properties.

For example, some prodrugs are esters of the active compound (e.g. a physiologically acceptable metabolically labile ester). During metabolism, the ester group (—C(═O)OR) is cleaved to yield the active drug. Such esters may be formed by esterification, for example, of any of the carboxylic acid groups (—C(═O)OH) in the parent compound, with, where appropriate, prior protection of any other reactive groups present in the parent compound, followed by deprotection if required. Examples of such metabolically labile esters include those wherein R is C₁₋₇ alkyl (e.g. -Me, -Et); C₁₋₇ aminoalkyl (e.g. aminoethyl; 2-(N,N-diethylamino)ethyl; 2-(4-morpholino)ethyl); and acyloxy-C₁₋₇alkyl (e.g. acyloxymethyl; acyloxyethyl; e.g. pivaloyloxymethyl; acetoxymethyl; 1-acetoxyethyl; 1-(1-methoxy-1-methyl)ethyl-carbonxyloxyethyl; 1-(benzoyloxy)ethyl; isopropoxy-carbonyloxymethyl; 1-isopropoxy-carbonyloxyethyl; cyclohexyl-carbonyloxymethyl; 1-cyclohexyl-carbonyloxyethyl; cyclohexyloxy-carbonyloxymethyl; 1-cyclohexyloxy-carbonyloxyethyl; (4-tetrahydropyranyloxy) carbonyloxymethyl; 1-(4-tetrahydropyranyloxy)carbonyloxyethyl; (4-tetrahydropyranyl)carbonyloxymethyl; and 1-(4-tetrahydropyranyl)carbonyloxyethyl).

Also, some prodrugs are activated enzymatically to yield the active compound, or a compound which, upon further chemical reaction, yields the active compound. For example, the prodrug may be a sugar derivative or other glycoside conjugate, or may be an amino acid ester derivative.

Selective Inhibition

‘Selective inhibition’ means the inhibition of one enzyme to a greater extent than the inhibition of one or more other enzymes. This selectivity is measurable by comparing the concentration of a compound required to inhibit 50% of the activity (IC₅₀) of one enzyme against the concentration of the same compound required to inhibit 50% of the activity (IC₅₀) of the other enzyme (see below). The result is expressed as a ratio. If the ratio is greater than 1, then the compound tested exhibits some selectivity in its inhibitory action.

The compounds of the present invention preferably exhibit a selectivity of greater than 3, 10, 20 or 50 against DNA-PK over PI 3-kinase.

The compounds of the present invention preferably exhibit a selectivity of greater than 5, 10, 50 or 100 against DNA-PK over ATM.

It is preferred that the IC₅₀s used to determine selectivity are determined using the methods described in WO 03/024949, which is herein incorporated by reference.

Further Preferences

When Q is —NH—C(═O)—, X is preferably NR⁴R⁵. It is further preferred that Y is an optionally substituted C₁₋₃ alkylene group, more preferably an optionally substituted C₁₋₂ alkylene group and most preferably a C₁₋₂ alkylene group.

When Q is —O— and X is NR⁴R⁵, then Y is preferably an optionally substituted C₁₋₃ alkylene group, more preferably an optionally substituted C₁₋₂ alkylene group and most preferably a C₁₋₂ alkylene group.

In some embodiments, R⁴ and R⁵ are preferably independently selected from H and optionally substituted C₁₋₇ alkyl, more preferably H and optionally substituted C₁₋₄ alkyl and most preferably H and optionally substituted C₁₋₂ alkyl. Preferred optional substitutents include, but are not limited to, hydroxy, methoxy, —NH₂, optionally substituted C₆-aryl and optionally substituted C₅₋₆ heterocyclyl.

In other embodiments, R⁴ and R⁵ form, together with the nitrogen atom to which they are attached, an optionally substituted nitrogen containing heterocylic ring having from 4 to 8 ring atoms. Preferably, the heterocyclic ring has 5 to 7 ring atoms. Examples of preferred groups include, morpholino, piperidinyl, piperazinyl, homopiperazinyl and tetrahydropyrrolo. These groups may be substituted, and a particularly preferred group is optionally substituted piperazinyl, where the substituent is preferably on the para-nitrogen atom. Preferred N-substituents include optionally substituted C₁₋₄ alkyl, optionally substituted C₆ aryl and acyl (with a C₁₋₄ alkyl group as the acyl substituent).

Some preferred compounds of the present invention can be represented by formula II:

wherein: R¹, R² and Q are as defined for formula I; n is 1 to 7, preferably 1-4 and most preferably 1 or 2; and R⁸ is selected from hydrogen, optionally substituted C₁₋₇ alkyl (preferably optionally substituted C₁₋₄ alkyl), optionally substituted C₅₋₂₀ aryl (preferably optionally substituted C₆ aryl), and acyl (where the acyl substituent is preferably C₁₋₄ alkyl).

The preferences for R⁶ and R⁷ may be the same as for R⁴ and R⁵ expressed above.

In formula I (and formula II), when R¹ and R² form, along with the nitrogen atom to which they are attached, a heterocyclic ring having from 4 to 8 atoms, this may form part of a C₄₋₂₀ heterocyclyl group defined above (except with a minimum of 4 ring atoms), which must contain at least one nitrogen ring atom. It is preferred that R¹ and R² form, along with the nitrogen atom to which they are attached, a heterocyclic ring having 5, 6 or 7 atoms, more preferably 6 ring atoms.

Single rings having one nitrogen atom include azetidine, azetidine, pyrrolidine (tetrahydropyrrole), pyrroline (e.g., 3-pyrroline, 2,5-dihydropyrrole), 2H-pyrrole or 3H-pyrrole (isopyrrole, isoazole), piperidine, dihydropyridine, tetrahydropyridine, and azepine; two nitrogen atoms include imidazolidine, pyrazolidine (diazolidine), imidazoline, pyrazoline (dihydropyrazole), and piperazine; one nitrogen and one oxygen include tetrahydrooxazole, dihydrooxazole, tetrahydroisoxazole, dihydroisoxazole, morpholine, tetrahydrooxazine, dihydrooxazine, and oxazine; one nitrogen and one sulphur include thiazoline, thiazolidine, and thiomorpholine.

Preferred rings are those containing one heteroatom in addition to the nitrogen, and in particular, the preferred heteroatoms are oxygen and sulphur. Thus preferred groups include morpholino, thiomorpholino, thiazolinyl. Preferred groups without a further heteroatom include pyrrolidino.

The most preferred groups are morpholino and thiomorpholino.

As mentioned above, these heterocyclic groups may themselves be substituted; a preferred class of substituent is a C₁₋₇ alkyl group. When the heterocyclic group is morpholino, the substituent group or groups are preferably methyl or ethyl, and more preferably methyl. A sole methyl substituent is most preferably in the 2 position.

As well as the single ring groups listed above, rings with bridges or cross-links are also envisaged. Examples of these types of ring where the group contains a nitrogen and an oxygen atom are:

These are named 8-oxa-3-aza-bicyclo[3.2.1]oct-3-yl, 6-oxa-3-aza-bicyclo[3.1.0]hex-3-yl, 2-oxa-5-aza-bicyclo[2.2.1]hept-5-yl, and 7-oxa-3-aza-bicyclo[4.1.0]hept-3-yl, respectively.

General Synthesis Methods

Compounds of formula I, where Q is —NH—C(═O)— can be represented as Formula 1:

These compounds, where —Y—X is not C₁₋₇ alkyl, can be made from compounds of formula 2:

wherein L is chloro or bromo, by reacting with the appropriate amine or thiol. This reaction can be carried at room temperature, or may be heated, if necessary.

Compounds of formula 2 can be synthesised by the reaction of a compound of formula 3:

with a compound of formula 4:

in the presence of an organic base, for example, triethylamine.

Compounds of formula 1 where —Y—X is C₁₋₇ alkyl can be synthesised by the reaction of a compound of formula 3 with a compound of formula 4a:

in the presence of an organic base, for example, triethylamine.

The compounds of formula 3 may be synthesised by reducing a compound of formula 5:

using an appropriate reducing agent, for example, zinc in acetic acid.

Compounds of formula 5 can be synthesised by the Suzuki-Miyaura coupling of compounds of formula 6 and 7:

This method is described in WO 03/024949 (Synthesis route 7c)—the boronic ester used can be replaced by equivalent boron groups.

Routes to compounds of formula 7 are described in WO 03/024949 (Synthesis Route 6).

Compounds of formula 1 where —Y—X is C₁₋₇ alkyl can also be synthesised by the Suzuki-Miyaura coupling compounds of formula 8 and 9:

Compounds of formula 8 may be synthesised from a compound of formula 10:

by reaction with the appropriate acid anhydride in, for example, pyridine.

Compounds of formula 9 may be synthesised from compounds of formula 8 by reaction with the appropriate boron reagent.

Compounds of formula I, where Q is —O— and X is selected from SR³ or NR⁴R⁵ can be represented as Formula 11:

wherein X′ represents SR³ or NR⁴R⁵. These compounds can be synthesised from compounds of formula 12:

wherein L is chloro or bromo, by reacting with the appropriate amine or thiol. This reaction can be carried at room temperature, or may be heated, if necessary.

Compounds of formula 12 can be synthesised by the reaction of a compound of formula 13:

with a compound of formula 14:

in the presence of, for example, potassium carbonate.

Compounds of formula 13 can be synthesised from compounds of formula 3 using a diazotisation-hydrolysis procedure. This first converts the amino group into the diazonium fluoroborate salt, for example, using HBF₄ and butyl nitrite, which is then hydrolysed using, for example, aqueous copper (I) oxide-copper (II) nitrate.

Compounds of formula I, where Q is —O— and X is —C(═O)—NR⁶R⁷ can be represented as Formula 15:

wherein X″ represents NR⁶R⁷. These compounds can be synthesised from compounds of formula 16:

by reaction with the appropriate amine in the presence of HBTU and HOBT.

Compounds of formula 16 can be made from compounds of formula 17:

by reaction with sodium hydroxide in methanol. The compounds of formula 17 can be synthesised from compounds of formula 10 by reaction with a compound of formula 18:

in the presence of, for example, potassium carbonate. Use of Compounds of the Invention

The present invention provides active compounds, specifically, active 8-[1-substituted-dibenzothiophen-4-yl]-2-morpholin-4-yl-chromen-4-ones.

The term “active”, as used herein, pertains to compounds which are capable of inhibiting DNA-PK activity, and specifically includes both compounds with intrinsic activity (drugs) as well as prodrugs of such compounds, which prodrugs may themselves exhibit little or no intrinsic activity.

One assay which may be used in order to assess the DNA-PK inhibition offered by a particular compound is described in the examples below.

The present invention further provides a method of inhibiting DNA-PK inhibition in a cell, comprising contacting said cell with an effective amount of an active compound, preferably in the form of a pharmaceutically acceptable composition. Such a method may be practised in vitro or in vivo.

For example, a sample of cells (e.g. from a tumour) may be grown in vitro and an active compound brought into contact with said cells in conjunction with agents that have a known curative effect, and the enhancement of the curative effect of the compound on those cells observed.

The present invention further provides active compounds which inhibit DNA-PK activity as well as methods of methods of inhibiting DNA-PK activity comprising contacting a cell with an effective amount of an active compound, whether in vitro or in vivo.

The invention further provides active compounds for use in a method of treatment of the human or animal body. Such a method may comprise administering to such a subject a therapeutically-effective amount of an active compound, preferably in the form of a pharmaceutical composition.

The term “treatment”, as used herein in the context of treating a condition, pertains generally to treatment and therapy, whether of a human or an animal (e.g. in veterinary applications), in which some desired therapeutic effect is achieved, for example, the inhibition of the progress of the condition, and includes a reduction in the rate of progress, a halt in the rate of progress, amelioration of the condition, and cure of the condition. Treatment as a prophylactic measure (i.e. prophylaxis) is also included.

The term “therapeutically-effective amount” as used herein, pertains to that amount of an active compound, or a material, composition or dosage from comprising an active compound, which is effective for producing some desired therapeutic effect, commensurate with a reasonable benefit/risk ratio.

Administration

The active compound or pharmaceutical composition comprising the active compound may be administered to a subject by any convenient route of administration, whether systemically/peripherally or at the site of desired action, including but not limited to, oral (e.g. by ingestion); topical (including e.g. transdermal, intranasal, ocular, buccal, and sublingual); pulmonary (e.g. by inhalation or insufflation therapy using, e.g. an aerosol, e.g. through mouth or nose); rectal; vaginal; parenteral, for example, by injection, including subcutaneous, intradermal, intramuscular, intravenous, intraarterial, intracardiac, intrathecal, intraspinal, intracapsular, subcapsular, intraorbital, intraperitoneal, intratracheal, subcuticular, intraarticular, subarachnoid, and intrasternal; by implant of a depot, for example, subcutaneously or intramuscularly.

The subject may be a eukaryote, an animal, a vertebrate animal, a mammal, a rodent (e.g. a guinea pig, a hamster, a rat, a mouse), murine (e.g. a mouse), canine (e.g. a dog), feline (e.g. a cat), equine (e.g. a horse), a primate, simian (e.g. a monkey or ape), a monkey (e.g. marmoset, baboon), an ape (e.g. gorilla, chimpanzee, orangutan, gibbon), or a human.

Formulations

While it is possible for the active compound to be administered alone, it is preferable to present it as a pharmaceutical composition (e.g. formulation) comprising at least one active compound, as defined above, together with one or more pharmaceutically acceptable carriers, adjuvants, excipients, diluents, fillers, buffers, stabilisers, preservatives, lubricants, or other materials well known to those skilled in the art and optionally other therapeutic or prophylactic agents.

Thus, the present invention further provides pharmaceutical compositions, as defined above, and methods of making a pharmaceutical composition comprising admixing at least one active compound, as defined above, together with one or more pharmaceutically acceptable carriers, excipients, buffers, adjuvants, stabilisers, or other materials, as described herein.

The term “pharmaceutically acceptable” as used herein pertains to compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgement, suitable for use in contact with the tissues of a subject (e.g. human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. Each carrier, excipient, etc. must also be “acceptable” in the sense of being compatible with the other ingredients of the formulation.

Suitable carriers, excipients, etc. can be found in standard pharmaceutical texts, for example, Remington's Pharmaceutical Sciences, 18th edition, Mack Publishing Company, Easton, Pa., 1990.

The formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. Such methods include the step of bringing into association the active compound with the carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association the active compound with liquid carriers or finely divided solid carriers or both, and then if necessary shaping the product.

Formulations may be in the form of liquids, solutions, suspensions, emulsions, elixirs, syrups, tablets, losenges, granules, powders, capsules, cachets, pills, ampoules, suppositories, pessaries, ointments, gels, pastes, creams, sprays, mists, foams, lotions, oils, boluses, electuaries, or aerosols.

Formulations suitable for oral administration (e.g. by ingestion) may be presented as discrete units such as capsules, cachets or tablets, each containing a predetermined amount of the active compound; as a powder or granules; as a solution or suspension in an aqueous or non-aqueous liquid; or as an oil-in-water liquid emulsion or a water-in-oil liquid emulsion; as a bolus; as an electuary; or as a paste.

A tablet may be made by conventional means, e.g., compression or moulding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine the active compound in a free-flowing form such as a powder or granules, optionally mixed with one or more binders (e.g. povidone, gelatin, acacia, sorbitol, tragacanth, hydroxypropylmethyl cellulose); fillers or diluents (e.g. lactose, microcrystalline cellulose, calcium hydrogen phosphate); lubricants (e.g. magnesium stearate, talc, silica); disintegrants (e.g. sodium starch glycolate, cross-linked povidone, cross-linked sodium carboxymethyl cellulose); surface-active or dispersing or wetting agents (e.g. sodium lauryl sulfate); and preservatives (e.g. methyl p-hydroxybenzoate, propyl p-hydroxybenzoate, sorbic acid). Moulded tablets may be made by moulding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent. The tablets may optionally be coated or scored and may be formulated so as to provide slow or controlled release of the active compound therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile. Tablets may optionally be provided with an enteric coating, to provide release in parts of the gut other than the stomach.

Formulations suitable for topical administration (e.g. transdermal, intranasal, ocular, buccal, and sublingual) may be formulated as an ointment, cream, suspension, lotion, powder, solution, past, gel, spray, aerosol, or oil. Alternatively, a formulation may comprise a patch or a dressing such as a bandage or adhesive plaster impregnated with active compounds and optionally one or more excipients or diluents.

Formulations suitable for topical administration in the mouth include losenges comprising the active compound in a flavoured basis, usually sucrose and acacia or tragacanth; pastilles comprising the active compound in an inert basis such as gelatin and glycerin, or sucrose and acacia; and mouthwashes comprising the active compound in a suitable liquid carrier.

Formulations suitable for topical administration to the eye also include eye drops wherein the active compound is dissolved or suspended in a suitable carrier, especially an aqueous solvent for the active compound.

Formulations suitable for nasal administration, wherein the carrier is a solid, include a coarse powder having a particle size, for example, in the range of about 20 to about 500 microns which is administered in the manner in which snuff is taken, i.e. by rapid inhalation through the nasal passage from a container of the powder held close up to the nose. Suitable formulations wherein the carrier is a liquid for administration as, for example, nasal spray, nasal drops, or by aerosol administration by nebuliser, include aqueous or oily solutions of the active compound.

Formulations suitable for administration by inhalation include those presented as an aerosol spray from a pressurised pack, with the use of a suitable propellant, such as dichlorodifluoromethane, trichlorofluoromethane, dichloro-tetrafluoroethane, carbon dioxide, or other suitable gases.

Formulations suitable for topical administration via the skin include ointments, creams, and emulsions. When formulated in an ointment, the active compound may optionally be employed with either a paraffinic or a water-miscible ointment base. Alternatively, the active compounds may be formulated in a cream with an oil-in-water cream base. If desired, the aqueous phase of the cream base may include, for example, at least about 30% w/w of a polyhydric alcohol, i.e., an alcohol having two or more hydroxyl groups such as propylene glycol, butane-1,3-diol, mannitol, sorbitol, glycerol and polyethylene glycol and mixtures thereof. The topical formulations may desirably include a compound which enhances absorption or penetration of the active compound through the skin or other affected areas. Examples of such dermal penetration enhancers include dimethylsulfoxide and related analogues.

When formulated as a topical emulsion, the oily phase may optionally comprise merely an emulsifier (otherwise known as an emulgent), or it may comprises a mixture of at least one emulsifier with a fat or an oil or with both a fat and an oil. Preferably, a hydrophilic emulsifier is included together with a lipophilic emulsifier which acts as a stabiliser. It is also preferred to include both an oil and a fat. Together, the emulsifier(s) with or without stabiliser(s) make up the so-called emulsifying wax, and the wax together with the oil and/or fat make up the so-called emulsifying ointment base which forms the oily dispersed phase of the cream formulations.

Suitable emulgents and emulsion stabilisers include Tween 60, Span 80, cetostearyl alcohol, myristyl alcohol, glyceryl monostearate and sodium lauryl sulphate. The choice of suitable oils or fats for the formulation is based on achieving the desired cosmetic properties, since the solubility of the active compound in most oils likely to be used in pharmaceutical emulsion formulations may be very low. Thus the cream should preferably be a non-greasy, non-staining and washable product with suitable consistency to avoid leakage from tubes or other containers. Straight or branched chain, mono- or dibasic alkyl esters such as di-isoadipate, isocetyl stearate, propylene glycol diester of coconut fatty acids, isopropyl myristate, decyl oleate, isopropyl palmitate, butyl stearate, 2-ethylhexyl palmitate or a blend of branched chain esters known as Crodamol CAP may be used, the last three being preferred esters. These may be used alone or in combination depending on the properties required.

Alternatively, high melting point lipids such as white soft paraffin and/or liquid paraffin or other mineral oils can be used.

Formulations suitable for rectal administration may be presented as a suppository with a suitable base comprising, for example, cocoa butter or a salicylate.

Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or spray formulations containing in addition to the active compound, such carriers as are known in the art to be appropriate.

Formulations suitable for parenteral administration (e.g. by injection, including cutaneous, subcutaneous, intramuscular, intravenous and intradermal), include aqueous and non-aqueous isotonic, pyrogen-free, sterile injection solutions which may contain anti-oxidants, buffers, preservatives, stabilisers, bacteriostats, and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents, and liposomes or other microparticulate systems which are designed to target the compound to blood components or one or more organs. Examples of suitable isotonic vehicles for use in such formulations include Sodium Chloride Injection, Ringer's Solution, or Lactated Ringer's Injection. Typically, the concentration of the active compound in the solution is from about 1 ng/ml to about 10 μg/ml, for example from about 10 ng/ml to about 1 μg/ml. The formulations may be presented in unit-dose or multi-dose sealed containers, for example, ampoules and vials, and may be stored in a freeze-dried (lyophilised) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules, and tablets. Formulations may be in the form of liposomes or other microparticulate systems which are designed to target the active compound to blood components or one or more organs.

Dosage

It will be appreciated that appropriate dosages of the active compounds, and compositions comprising the active compounds,

can vary from patient to patient. Determining the optimal dosage will generally involve the balancing of the level of therapeutic benefit against any risk or deleterious side effects of the treatments of the present invention. The

selected dosage level will depend on a variety of factors including, but not limited to, the activity of the particular

compound, the route of administration, the time of administration, the rate of excretion of the compound, the duration of the treatment, other drugs, compounds, and/or materials used in combination, and the age, sex, weight, condition, general health, and prior medical history of the patient. The amount of compound and route of administration will ultimately be at the discretion of the physician, although generally the dosage will be to achieve local concentrations at the site of action which achieve the desired effect without causing substantial harmful or deleterious side-effects.

Administration in vivo can be effected in one dose, continuously or intermittently (e.g. in divided doses at appropriate intervals) throughout the course of treatment. Methods of determining the most effective means and dosage of administration are well known to those of skill in the art and will vary with the formulation used for therapy, the purpose of the therapy, the target cell being treated, and the subject being treated. Single or multiple administrations can be carried out with the dose level and pattern being selected by the treating physician.

In general, a suitable dose of the active compound is in the range of about 100 μg to about 250 mg per kilogram body weight of the subject per day. Where the active compound is a salt, an ester, prodrug, or the like, the amount administered is calculated on the basis of the parent compound and so the actual weight to be used is increased proportionately.

EXAMPLES

The following are examples are provided solely to illustrate the present invention and are not intended to limit the scope of the invention, as described herein.

Acronyms

For convenience, many chemical moieties are represented using well known abbreviations, including but not limited to, methyl (Me), ethyl (Et), n-propyl (nPr), iso-propyl (iPr), n-butyl (nBu), tert-butyl (tBu), n-hexyl (nHex), cyclohexyl (cHex), phenyl (Ph), biphenyl (biPh), benzyl (Bn), naphthyl (naph), methoxy (MeO), ethoxy (EtO), benzoyl (Bz), and acetyl (Ac).

For convenience, many chemical compounds are represented using well known abbreviations, including but not limited to, methanol (MeOH), ethanol (EtOH), iso-propanol (i-PrOH), methyl ethyl ketone (MEK), ether or diethyl ether (Et₂O), acetic acid (AcOH), dichloromethane (methylene chloride, DCM), trifluoroacetic acid (TFA), dimethylformamide (DMF), tetrahydrofuran (THF), and dimethylsulfoxide (DMSO).

General Experimental Methods

Thin layer chromatography was carried out using Merck Kieselgel 60 F₂₅₄ glass backed plates. The plates were visualised by the use of a UV lamp (254 nm). Silica gel 60 (particle sizes 40-63μ) supplied by E. M. Merck was employed for flash chromatography. ¹H NMR spectra were recorded at 300 MHz on a Bruker DPX-300 instrument. Chemical shifts were referenced to tetramethylsilane.

Purification and Identification of Library Samples

The samples were purified on Gilson LC units. Mobile phase A—0.1% aqueous TFA, Mobile phase B—Acetonitrile, Flow rate 6 ml/min., Gradient—typically starting at 90% A/10% B for one minute, rising to 97% B after 15 minutes, holding there for 2 minutes, then back to the starting conditions. Column: Jones Chromatography Genesis 4μ C18 column, 10 mm×250 mm. Peak acquisition based on UV detection at 254 nm.

Mass spectra were recorded on a Finnegan LCQ instrument in positive ion mode. Mobile phase A—0.1% aqueous formic acid, Mobile phase B—Acetonitrile, Flow rate 2 ml/min., Gradient—starting at 95% A/5% B for one minute, rising to 98% B after 5 minutes, holding there for 3 minutes, then back to the starting conditions. Column: Phenomenex 5μ Luna C18 column, 4.6 mm×50 mm. UV detection at 254 nm, PDA detection scanning from 210 to 600 nm.

Mass Spectra of Other Compounds

Mass spectra of non-library compounds and intermediates were recorded on a Micromass ZQ instrument (single quadrupole, operating in electrospray ionisation mode), using a Waters 600 HPLC pump and 2700 Autosampler.

Mobile phase A—0.1% formic acid in water, Mobile phase B—0.1% formic acid in acetonitrile, Flow rate 2.0 ml/min., Gradient: 5% B to 95% B over 3 minutes, holding there for 3 minutes. Column: Varies, but always C18 50 mm×4.6 mm (Currently Genesis 4μ, Jones Chromatography). PDA detection: Waters 996, scan range 210-400 nm.

Synthesis of Key Intermediates (a) Morpholin-4-yl-8-(1′-nitrodibenzothiophen-4′-yl)chromen-4-one (viii)

Dibenzothiophen-4-ol (i)

To a cooled (−78° C.) solution of dibenzothiophene (20.8 g, 113 mmol) in anhydrous THF (400 ml) was added tert-butyl lithium (1.7 M in pentane; 100 ml, 170 mmol). The reaction mixture was stirred at −78° C. for 1 hour and then allowed to warm to room temperature and stirred like this for 16 hours. The mixture was then cooled to 0° C. and ethylmagnesium bromide (1M in THF; 170 ml, 170 mmol) added to the amber reaction mixture in a slow stream via cannula. The reaction was again allowed to room temperature whereupon it was stirred like this for 30 minutes. A reflux condenser was attached to the reaction vessel before oxygen was bubbled through the solution for 40 minutes. The mixture was then stirred for a further 1 hour before carefully pouring onto crushed ice and acidifying to pH 3 with concentrated HCl. The mixture was then extracted using ethyl acetate (3×80 ml). The organic extracts were then treated with 3M sodium hydroxide solution until pH 10 was attained. The basic, aqueous layer was separated, acidified to pH 3 with 2M HCl which caused an oily solid to precipitate. This was dissolved in diethylether (150 ml), dried using MgSO₄, filtered and concentrated in vacuo and then recrystallised from ethanol:water (1:1) (250 ml) to give a buff coloured solid that corresponded to the title compound (21.6 g, 96%) and required no further purification. m/z (LC-MS, ESP), RT=3.64 min, (M+H)=201.1

4-Methoxy-dibenzothiophene (ii)

To a solution of dibenzothiophen-4-ol (i)(14.2 g, 71.0 mmol) in acetone (500 ml) was added powdered potassium carbonate (14.72 g, 106.5 mmol) and methyl iodide (4.43 ml, 71 mmol). The mixture was heated to reflux and stirred like this for 16 hours. The mixture was then cooled and filtered through a Celite™ pad. The resulting filtrant was concentrated in vacuo to give an oily residue that was diluted in dichloromethane (100 ml) and washed with 1M NaOH and saturated brine solution. The organic layer was dried using MgSO₄, filtered and concentrated in vacuo to give a buff coloured solid that corresponded to the title compound and was used without any further purification. (15.2 g, 100%) m/z (LC-MS, ESP), RT=4.22 min, (M+H)=215.1

4-Methoxy-1-nitro-dibenzothiophene (iii)

4-Methoxy-dibenzothiophene (ii)(4.3 g, 20.0 mmol) was dissolved in glacial acetic acid (60 ml) and to this solution was added fuming nitric acid (3.37 ml) in a dropwise fashion ensuring that the temperature of the mixture did not rise above 25° C. The yellow suspension was stirred for a further 45 minutes before being poured carefully into water (200 ml) and stirred for 15 minutes. The yellow solid was removed by filtration and washed thoroughly with copious amounts of water and then hexanes. The residue thus obtained was then dried in a vacuum oven to give the title compound as a yellow solid which was used without any further purification. (5.19 g, 97%) m/z (LC-MS, ESP), RT=4.15 min, (M+H)=260.1

1-Nitro-dibenzothiophen-4-ol (iv)

Solid pyridine hydrochloride (1 kg, 8.7 mol) was added to 4-methoxy-1-nitro-dibenzothiophene (iii)(35.44 g, 187 mmol) and the reaction mixed well before heating to 165° C. with continuous stirring. The mixture was maintained like this for 8 hrs, cooled, diluted with water (500 ml) and extracted into dichloromethane (3×200 ml). 3M sodium hydroxide solution was added to the organic extract until a dark solid precipitated from the solution. The filtrate was removed and the liquor acidified to pH1 using concentrated HCl. The resulting bright yellow solid that formed on acidification was then removed by filtration, washed with water and dried to give the title compound that was suitably pure to be used without any further purification. (35.44 g, 77%) m/z (LC-MS, ESP), RT=3.69 min, (M+H)=246.2, (M−H)=244.1

Trifluoro-methanesulfonic acid 1-nitro-dibenzothiophen-4-yl ester (v)

To a cooled (−5° C.) suspension of 1-nitro-dibenzothiophen-4-ol (iv)(5.37 g, 22.0 mmol) in dichloromethane (75 ml) was added triethylamine (9.20 ml, 66.00 mmol) which caused the suspension to solublise completely. To this mixture was then added trifluoromethanesulfonic anhydride (5.85 ml, 33.00 mmol) in a dropwise fashion via syringe. The mixture was stirred at this temperature for 1 hour and then poured onto crushed ice. The ice was allowed to melt and the mixture extracted using CH₂Cl₂ (3×20 ml). The combined organic layers were then dried (MgSO₄), filtered and concentrated in vacuo to give a mild amber oil that was eluted though a pad of silica (neat CH₂Cl₂) to give the title compound in a suitably pure form to be used without any further purification. (8.30 g, 99%) %) m/z (LC-MS, ESP), RT=4.40 min, did not ionize.

Morpholin-4-yl-8-(1′-nitrodibenzothiophen-4′-yl)chromen-4-one (viii)

A clean, dry flask was charged with trifluoro-methanesulfonic acid 1-nitro-dibenzothiophen-4-yl ester (v) (250 mg, 0.66 mmol), bis(pinacolato)diboron (185 mg, 0.73 mmol), potassium acetate (390 mg, 3.98 mmol), PdCl₂(dppf) (27 mg, 0.033 mmol), and dppf (19 mg, 0.033 mmol) under argon. The flask was evacuated under vacuum and flushed with argon three times. Dioxane (20 ml) was added and the reaction mixture was stirred at 90° C. for 12 hours. The reaction mixture was diluted with DCM (100 ml) and organic layer was washed successively with water (3×30 ml), brine (1×30 ml), dried (Na₂SO₄) and the solvent was evaporated in vacuo to furnish the nitroboronate ester (vi) which was used without further purification. A mixture of vi (280 mg, 0.79 mmol), chromenone-8-triflate (vii) (298 mg, 0.79 mmol), PdCl₂(dppf) (19.3 mg, 0.024 mmol), and Cs₂CO₃ (770 mg, 2.36 mmol) was flushed three times with argon, and THF (20 ml) was added. The reaction mixture was stirred under reflux for 12 hours. The solvents was removed in vacuo and the residue was dissolved in DCM, (100 ml) washed with water (2×30 ml), brine (1×30 ml), dried (Na₂SO₄) and the solvent was evaporated in vacuo to furnish the title compound (viii). The crude product was purified by column chromatography using 2-5% methanol in DCM.

m.p=179° C.; R_(f)=0.28 (DCM/MeOH 95/5); LC-MS ES⁺460. IR (film): 1681, 1619, 1559, 1404 cm⁻¹; UV: λ_(max)=240 nm. ¹H NMR (300 MHz, CDCl₃): δ 8.27 (dd, J=7.8; 1.6 Hz, 1H); 8.09 (d, J=7.5 Hz, 1H); 7.83 (d, J=7.9 Hz, 1H); 7.78 (d, J=7.1 Hz, 1H); 7.66 (dd, J=7.5; 1.6 Hz, 1H); 7.42-7.52 (m, 4H); 5.45 (s, 1H); 3.40-3.47 (m, 4H); 3.00-3.03 (m, 4H). ¹³C NMR (75 MHz, CDCl₃): δ 176.9; 162.5; 150.8; 151.7; 143.4; 140.5; 135.9; 133.5; 131.6; 129.0; 127.5; 127.4; 127.0; 125.8; 125.6; 125.4; 124.1; 123.1; 120.8; 87.6; 66.0; 44.9.

(b) 8-(1′-Aminodibenzothiophen-4′-yl)-2-morpholin-4-yl-chromen-4-one (ix)

To a solution of the nitrodibenzothiophene derivative (viii) (810 mg, 1.77 mmol) in acetic acid (30 ml) was added zinc powder (1.16 g, 17.70 mmol) and the reaction mixture was stirred at room temperature overnight. The reaction mixture was filtered through celite, washed successively with methanol (4×50 ml) and DCM (2×50 ml) and the combined filtrates were evaporated under reduced pressure. The residual solid was stirred with water (100 ml) and aqueous ammonia (25 ml) was added. The resultant precipitated solid was collected by filtration, and purified by chromatography on silica employing 2-5% methanol in DCM as eluent.

R_(f)=0.28 (DCM/MeOH 95/5); IR (film): 3326, 3211, 2962, 2902, 2851, 1729, 1615, 1555. ¹H NMR (300 MHz, CDCl₃): δ 8.14-8.20 (m, 2H); 7.74 (dd, J=7.7; 1.1 Hz, 1H); 7.67 (dd, J=7.4; 1.7 Hz, 1H); 7.34-7.49 (m, 4H); 7.22 (d, J=7.8 Hz, 1H); 6.82 (d, J=7.8 Hz, 1H); 5.48 (s, 1H, ═CH); 4.55 (br, —NH, 2H); 3.42-3.46 (m, 4H); 3.03-3.06 (m, 4H). ¹³C NMR (75 MHz, CDCl₃): δ 177.6; 162.5; 151.7; 144.2; 141.6; 138.9; 135.8; 134.1; 132.8; 129.1; 128.9; 126.0; 125.7; 125.3; 125.1; 125.0; 123.8; 123.7; 123.1; 123.0; 122.0; 113.1; 87.18; 66.4; 45.0.

(c) 2-Chloro-N-[4-(2-morpholin-4-yl-4-oxo-4H-chromen-8-yl)-dibenzothiophen-1-yl]-acetamide (A)

To a solution of the aminodibenzothiophene derivative (ix, 1 mol. equiv.) in dry DMA (12 ml) was added triethylamine (2.2 mol. equiv.) and chloroacetyl chloride (1.1 mol. equiv.), and the reaction mixture was stirred at room temperature for 4 hours.

(d) 3-Bromo-N-[4-(2-morpholin-4-yl-4-oxo-4H-chromen-8-yl)-dibenzothiophen-1-yl]-propionamide (B)

To a solution of the aminodibenzothiophene derivative (ix; 1 mol. equiv.) in dry DMA, was added triethylamine (2.2 mol. equiv.) and 3-bromopropionyl chloride (1.1 mol. equiv.), and the reaction mixture was stirred at room temperature for 4 hours.

(e) 8-(1-Hydroxy-dibenzothiophen-4-yl)-2-morpholin-4-yl-chromen-4-one (x)

The aminodibenzothiophene derivative (ix) (1 mmol) was suspended in ethanol (40 ml) and HBF₄ (15 mmol) was added dropwise at room temperature. After stirring for 15 minutes the reaction mixture became a clear solution, which was cooled to 0° C. and t-butylnitrite (2 mmol) was added. After 30 minutes the reaction mixture was diluted with ether (80 ml). The precipitated solid was filtered, washed with ether (2×20 ml) and dried. This solid was added to a solution of cupric nitrate (300 mmol) in 1 L of water containing cuprous oxide (1 mmol) and stirred for 1 hour at room temperature. The aqueous solution was filtered to afford the product as brown solid, which was purified by column chromatography on silica using 2-5% methanol/DCM.

(f) 8-[1-(2-Bromo-ethoxy)-dibenzothiophen-4-yl]-2-morpholin-4-yl-chromen-4-one (C)

To a solution of the 1-hydroxydibenzothiophene (x; 1 mol. equiv.) in dry DMF (20 ml) was added potassium carbonate (1.1 mol. equiv.) and dibromoethane (1.1 mol. equiv.), and the reaction mixture was stirred at room temperature for 12 hours.

(g) Sodium [4-(2-Morpholin-4-yl-4-oxo-4H-chromen-8-yl)-dibenzothiophen-1-yloxy]-acetate (D)

The hydroxyl compound (x) was suspended in dry DMF, potassium carbonate was added followed by methyl bromoacetate, and the reaction mixture was stirred at 60° C. overnight. After completion of the reaction, the reaction mixture was poured into water and extracted with ethyl acetate. The organic layer was washed with water, brine, dried and concentrated to give the methyl ester as a yellow solid. The progress of the reaction was monitored by HPLC and LC-MS. The ester was dissolved in methanol and aqueous NaOH was added. The reaction mixture was stirred at 60° C. for 1 hour, when HPLC and LC-MS showed the absence of the methyl ester. The reaction mixture was evaporated to dryness in vacuo to afford the sodium salt (D).

Example 1

Aliquots (0.5 ml) of 2-Chloro-N-[4-(2-morpholin-4-yl-4-oxo-4H-chromen-8-yl)-dibenzothiophen-1-yl]-acetamide (A) were added to each of the vials containing the various amines for the synthesis. The reaction mixtures were stirred in parallel at room temperature for 12 hours, diluted with a minimum volume of methanol, and the resulting compounds were then purified.

Compound R M/z Rt (min) Purity (%) 1

556.4 3.5 95 2

554.5 3.38 95 3

555.4 3.25 95 4

569.4 3.28 95 5

574.4 3.2 95 6

602.4 3.66 90 7

530.4 3.21 95 8

529.4 2.99 95 9

583.5 3.26 90 10

568.5 3.49 95 11

606.4 3.57 95 12

542.5 3.38 95 13

486.4 3.19 95 14

599.4 3.16 95 15

570.4 3.36 95 16

597.5 3.11 95 17

571.4 3.28 95 18

584.5 3.65 90 19

605.5 3.48 85 20

598.5 3.23 90 21

597.5 3 95 22

544.4 3.32 95 23

597.6 3.39 95 24

613.6 3.34 85 25

643.6 3.25 95 26

583.6 3.29 95 27

632.6 3.44 95 28

649.6 4.06 90 29

654.5 3.39 90 30

626.4 3.02 95 31

597.4 3.23 95 32

599.4 3.24 95 33

613.4 3.22 95 34

613.4 2.98 95 35

569.4 3.18 95 36

514.4 3.28 95 37

577.4 3.22 90 38

597.4 3.36 90 39

570.4 3.68 95 Representative Analytical Data

Compound 1: ¹H NMR (300 MHz, CDCl₃): δ 10.27 (1H, s, —NH), 8.44 (1H, m, Ar), 8.29 (1H, d, J=7.85 Hz, Ar), 8.04 (1H, d, J=8.04 Hz, Ar), 7.86 (2H, m, Ar), 7.55 (4H, m, Ar), 6.59 (1H, s, ═CH—), 4.01 (4H, m, —NCH₂CH₂—), 3.82 (2H, s, —NCH₂), 3.53 (4H, m, —NCH₂CH₂—), 3.26 (4H, m, —NCH₂CH₂—), 3.18 (4H, m, —NCH₂CH₂—). M.p.: 165° C.

Compound 2: ¹H NMR (300 MHz, CDCl₃): δ 10.80 (1H, s, —NH), 8.26 (1H, m, Ar), 8.19 (1H, dd, J=1.6 Hz, Ar), 7.70 (2H, m, Ar), 7.48 (2H, m, Ar), 7.38 (3H, m, Ar), 6.15 (1H, s, ═CH—), 4.10 (2H, s, —NCH₂), 3.42 (6H, m, —NCH₂CH₂—), 3.09 (7H, m, —NCH₂CH₂—), 1.95 (5H, m, —CH₂CH₂—). M.p.: 188° C.

Compound 17 (oil): ¹H NMR (300 MHz, CDCl₃): δ 10.15 (1H, s, —NH), 8.22 (2H, t, J=7.93 Hz, Ar), 7.74 (2H, t, J=7.64 Hz, Ar), 7.58 (1H, d, J=7.95 Hz, Ar), 7.50 (1H, d, J=7.67 Hz, Ar), 7.36 (3H, m, Ar), 6.58 (1H, s, ═CH—), 3.53 (2H, s, —NCH₂), 3.45 (4H, m, —NCH₂CH₂—), 3.20 (6H, m, —NCH₂CH₂—), 3.03 (2H, m, —NCH₂), 2.91 (6H, s, —NCH₃), 2.56 (3H, s, —NCH₃).

Compound 18: ¹H NMR (300 MHz, CDCl₃): δ 10.26 (1H, s, —NH), 8.32 (1H, d, J=6.42 Hz, Ar), 8.20, (1H, d, J=6.36 Hz, Ar), 7.90 (1H, m, Ar), 7.74 (2H, m, Ar), 7.47 (4H, m, Ar), 6.40 (1H, s, ═CH—), 3.96 (2H, m, —NCH₂), 3.77 (2H, s, —OCH₂), 3.44 (4H, m, —NCH₂CH₂—), 3.27 (2H, d, J=11.57 Hz, —NCH₂), 3.15 (4H, s, —NCH₂CH₂—), 2.50 (2H, m, —NCH₂). M.p.: 152° C.

Compound 27: ¹H NMR (300 MHz, CDCl₃): δ 9.90 (1H, s, —NH), 8.38 (1H, m, Ar), 8.22 (3H, m, Ar), 7.77 (3H, m, Ar), 7.45 (4H, m, Ar), 6.89 (2H, m, Ar), 6.32 (1H, S, ═CH—), 3.89 (2H, bs, —NCH₂), 3.51 (4H, s, —NCH₂CH₂—), 3.46 (4H, m, —NCH₂CH₂—), 3.17 (4H, m, —NCH₂CH₂—), 3.03 (4H, m, —NCH₂CH₂—). M.p.: 171° C.

Example 2

Aliquots (0.5 ml) of 3-Bromo-N-[4-(2-morpholin-4-yl-4-oxo-4H-chromen-8-yl)-dibenzothiophen-1-yl]-propionamide (B) were added to each of the vials containing the various amines for the synthesis. The reaction mixtures were stirred in parallel at room temperature for 12 hours, diluted with a minimum volume of methanol, and the resulting compounds were then purified.

Compound R M/z Rt (min) Purity (%) 40

570.5 3.29 95 41

568.4 3.39 95 42

569.4 3.15 95 43

583.4 3.22 95 44

588.4 3.23 95 45

544.4 3.23 95 46

543.4 2.98 95 47

597.4 3.03 85 48

582.5 3.44 95 49

620.5 3.58 95 50

556.5 3.38 95 51

500.3 3.26 95 52

613.5 3.13 95 53

584.4 3.43 95 54

611.5 3.03 95 55

585.4 3.08 95 56

598.4 3.38 90 57

619.4 3.33 95 58

612.4 3.25 95 59

611.4 3.01 95 60

558.3 3.35 90 61

611.4 3.25 90 62

627.4 3.24 95 63

657.4 3.2 95 64

597.4 3.23 95 65

646.4 3.33 95 66

663.4 3.73 95 67

647.5 3.45 85 68

668.5 3.37 85 69

640.1 3.03 90 70

611.4 3.02 85 71

613.5 3.18 85 72

627.5 2.99 95 73

627.5 3.02 95 74

591.3 3.13 95 75

611.3 3.27 95 76

584.5 3.73 95 Representative Analytical Data

Compound 48: ¹H NMR (300 MHz, CDCl₃): δ 9.32 (1H, s, —NH), 8.22 (2H, m, Ar), 7.73 (2H, m, Ar), 7.58 (1H, d, J=7.82 Hz, Ar), 7.40 (4H, m, Ar), 6.12 (1H, s, ═CH—) 3.54 (4H, m), 3.44 (4H, m), 3.29 (2H, m), 3.11 (6H, m), 2.37 (bs), 1.76 (m).

Compound 53: ¹H NMR (300 MHz, CDCl₃): δ 9.19 (1 h, s, —NH), 8.20 (2H, m, Ar), 7.69 (2H, m, Ar), 7.53 (1H, m, Ar), 7.41 (1H, m, Ar), 6.00 (1H, s, ═CH—), 4.16 (1H, m), 3.68 (2H, m), 3.42 (8H, m), 3.06 (4H, m), 2.62 (8H, m). M.p.: 148° C.

Example 3

Aliquots (0.5 ml) of 8-[1-(2-bromo-ethoxy)-dibenzothiophen-4-yl]-2-morpholin-4-yl-chromen-4-one (C) were added to each of the vials containing the various amines for the synthesis. The reaction mixtures were stirred in parallel at room temperature for 12 hours, diluted with a minimum volume of methanol, and the resulting compounds were then purified.

Rt Purity Compound R M/z (min) (%) 77

543.6 3.55 90 78

571.4 3.72 95 79

541.4 3.67 95 80

556.4 3.65 95 81

586.4 3.32 90 82

575.4 3.52 95 83

584.5 3.65 95 84

584.5 3.46 95 85

564.4 3.38 90 86

550.4 3.56 95 87

529.4 3.65 95 88

501.4 3.5 95 89

558.3 3.39 95 90

570.4 3.29 95 91

530.4 3.38 90 Representative Analytical Data

Compound 78: ¹H NMR (300 MHz, CDCl₃): δ 8.84 (1H, m, Ar0, 8.28 (1H, d, J=7.85 Hz, Ar), 7.76 (2H, m, Ar), 7.50 (3H, m, Ar), 7.35 (1H, d, J=8.22 Hz, Ar), 7.11 (1H, d, J=8.45 Hz, Ar), 5.95 (1H, s, ═CH), 5.07 (2H, d, J=9.50 Hz, —OCH₂), 4.47 (1H, d, —OCH(CH₃)), 3.96 (1H, d, —CH(CH₃)), 3.51 (8H, m, —NCH₂), 3.16 (4H, m, —NCH₂), 1.22 (3H, d, J=6.20 Hz, —CH₃), 1.12 (3H, d, J=6.24 Hz, —CH₃). M.p.: 240° C.

Compound 80: ¹H NMR (300 MHz, CDCl₃): δ 8.73 (1H, dd, J=5.12 Hz, Ar), 8.01 (1H, dd, J=7.85 Hz, Ar), 7.81 (1H, dd, J=7.54 Hz, Ar), 7.73 (1H, dd, J=7.42 Hz, ar), 7.51 (1H, d, J=8.23 Hz, Ar), 7.42 (3H, m, Ar), 7.19 (1H, d, J=8.35 Hz, Ar), 4.54 (2H, m, —OCH₂), 3.39 (8H, t, J=4.64 Hz, N—CH₂), 3.34 (2H, m, —N—CH₂), 3.10 (8H, t, J=4.81 Hz, N—CH₂), 2.81 (3H, s, —N—CH₃). M.p.: 100° C.

Compound 81: ¹H NMR (300 MHz, CDCl₃): δ 8.66 (1H, dd, J=9.39 Hz, Ar), 7.99 (1H, dd, J=6.19 Hz, Ar), 7.79 (1H, dd, J=5.97 Hz, Ar), 7.72 (1H, dd, J=7.44 Hz, Ar), 7.51 (1H, d, J=7.46 Hz, Ar), 7.38 (3H, m, Ar), 7.22 (1H, d, J=8.31 Hz, Ar), 4.76 (2H, t, J=5.58 Hz, —OCH₂), 3.79 (10H, m, —NCH₂ & —OCH₂), 3.58 (2H, m, —NCH₂), 3.38 (8H, t, J=5.06 Hz, —NCH₂), 3.20 (1H, s, —NH), 3.09 (2H, t, J=4.89 Hz, —NCH₂). M.p.: 70° C.

Compound 83: ¹H NMR (300 MHz, CDCl₃): δ 8.55 (1H, d, J=6.67 Hz, Ar), 7.99 (1H, dd, J=6.24 Hz, Ar), 7.72 (2H, m, Ar), 7.45 (4H, m, Ar), 6.99 (1H, d, J=8.27 Hz, Ar), 6.39 (1H, s, ═CH), 4.58 (2H, m, —OCH₂), 3.54 (3H, m, —CH(CH₃)₂ & —NCH₂), 3.45 (12H, m, —NCH₂), 3.17 (4H, m, —NCH₂), 1.32 (6H, d, J=6.67 Hz, (CH₃)₂CH—). M.p.: 158° C.

Compound 87: ¹H NMR (300 MHz, CDCl₃): δ 8.57 (1H, m, Ar), 8.29 (1H, d, J=7.85 Hz, Ar), 7.82 (2H, m, Ar), 7.51 (4H, m, Ar), 7.12 (1H, d, J=8.23 Hz, Ar), 6.59 (1H, s, ═CH), 4.85 (2H, m, —OCH₂), 3.78 (2H, m, —NCH₂), 3.54 (4H, m, —OCH₂), 3.47 (4H, m, —NCH₂), 3.28 (4H, m, —NCH₂), 1.47 (6H, t, J=7.38 Hz, —CH₃). M.p.: 147° C.

Compound 88: ¹H NMR (300 MHz, CDCl₃): δ 8.68 (1H, m, Ar), 8.02 (1H, dd, J=7.83 Hz, Ar), 7.82 (1H, m, Ar), 7.76 (1H, dd, J=7.34 Hz, Ar), 7.45 (1H, d, J=7.52 Hz, Ar), 7.40 (2H, m, Ar). 7.25 (1H, d, J=8.42 Hz, Ar), 4.84 (2H, m, —OCH₂), 3.92 (2H, m, —NCH₂), 3.39 (8H, m, —OCH₂), 3.11 (8H, m, —NCH₂), 3.05 (6H, s, (CH₃)₂N—). M.p.: 166° C.

Example 4

Sodium [4-(2-Morpholin-4-yl-4-oxo-4H-chromen-8-yl)-dibenzothiophen-1-yloxy]-acetate (D) was dissolved in DMF, and aliquoted in 15 equal portions into reaction tubes containing the appropriate amines. A solution of HBTU and HOBT in dry DMF was added to each tube, and the reaction mixtures were stirred at room temperature overnight. The resulting products were then purified.

Rt Purity Compound R M/z (min) (%) 92

585.4 4.67 95 93

555.4 4.78 95 94

570.4 3.49 95 95

589.4 4.04 95 96

598.5 3.6 95 97

598.5 3.99 95 98

578.5 3.6 95 99

572.4 3.54 95 100

584.5 3.53 95 101

544.4 3.75 95 102

488.4 4.26 95

Example 5 8-(1′-Acetylaminodibenzothiophen-4′-yl)-2-morpholin-4-yl-chromen-4-one (103)

(a) 4-Trifluoromethanesulfonyl-dibenzothiophen-1-ylamine (xi)

A solution of glacial acetic acid (80 mL) containing Zn powder (1.17 g, 17.96 mmol) and compound trifluoro-methanesulfonic acid 1-nitro-dibenzothiophen-4-yl ester (v)(1.13 g, 2.99 mmol, 1 equiv.) was stirred at room temperature overnight. Upon completion the solution was filtered through a Celite™ pad. The Celite™ cake was then washed with dichloromethane and the organic phase was concentrated in vacuo. The crude product was purified by flash chromatography (SiO₂) (DCM/petrol 4/6 then 6/4) leading to the desired compound as a white solid (0.84 g, 80% yield).

m.p=108° C.; R_(f)=0.34 (DCM/petrol 6/4); LC-MS m/z 348 [M+1]

¹H NMR (300 MHz, CDCl₃): δ 8.06-8.09 (m, 1H); 7.77-7.81 (m, 1H); 7.36-7.44 (m, 2H); 7.14 (d, J=8.6 Hz, 1H); 6.63 (d, J=8.6 Hz, 1H); 3.94 (s, NH₂). ¹³C NMR (75 MHz, CDCl₃): δ 143.9; 138.8; 136.9; 135.4; 134.1; 126.6; 125.4; 124.8; 123.6; 123.3; 119.7; 119.4 (q, J=317 Hz, CF₃); 113.0.

(b) 1-acetylaminodibenzothiophene triflate (xii)

To a solution of the aminodibenzothiophene triflate (200 mg, 0.58 mmol) in pyridine (4.0 ml), was added acetic anhydride (0.29 ml, 2.88 mmol) dropwise. The reaction mixture was stirred at room temperature for 12 hours, diluted with water (20 ml), and extracted with ethyl acetate (3×10 ml). The combined organic layers were washed successively with water (2×20 ml), saturated aqueous sodium bicarbonate solution (1×20 ml) and brine (1×20 ml), dried (Na₂SO₄) and evaporated in vacuo. The residual solid was triturated with petrol to give the title compound (xii).

LC/MS (in MeOH): Tr=3.15 min. ¹H NMR (300 MHz, CDCl₃): δ 9.51 (1H, s, NH), 8.48 (1H, d, J=8.1 Hz), 8.25 (1H, d, J=7.42 Hz), 7.71-7.53 (4H, m), 2.33 (3H, s, —CH₃). ¹³C NMR (75 MHz, CDCl₃): δ 139.81, 135.34, 129.05, 126.56, 124.19, 120.00, 24.09.

(c) 2-morpholin-4-yl-8-(4,4,5,5-tetramethyl-[1,3,2° dioxaborolan-4-yl)-4a,8a-dihydro-chromen-4-one (xiii)

A suspension of 2-morpholin-4-yl-8-trifluoromethanesulfonyl-chromen-4-one (vii)(1.0 g, 2.637 mmol), bis(pinacolato)diboron (0.803 g, 3.165 mmol) and potassium acetate (0.776 g, 7.911 mmol), 1,4-dioxane (30 mL) was degassed by bubbling nitrogen through the solution while sonicating for 15 min. To the reaction mixture was than added (1,1′-Bis(diphenylphosphino)ferrocene-dichloropalladium(II), (107 mg, 0.132 mmol) and 1,1-Bis(diphenylphosphino)ferrocene (73 mg, 0.132 mmol). The reaction was heated at 90° C. under N₂ for 16 hours. On completion the solution was diluted in ether and the organic layer was washed with a saturated NaCl solution, dried over MgSO₄ and concentrated in vacuum to give the title compound as a black solid (0.80 g, 85% yield) which was used without purification. LC-MS m/z 358 [M+1]; ¹H NMR (300 MHz, CDCl₃): δ 8.20 (d, J=6.3 Hz, 1H); 7.94 (d, J=7.2 Hz, 1H); 7.27 (t, J=7.5 Hz, 1H); 5.51 (s, 3H); 3.74-3.78 (m, 4H); 3.61-3.64 (m, 4H): 1.19 (s, 12H); ¹³C NMR (75 MHz, CDCl₃): δ 178.0; 162.0; 158.1; 140.6; 129.6; 124.7; 86.8; 84.3; 83.5; 66.5; 45.1; 25.4; 24.9.

(d) 8-(1′-Acetylaminodibenzothiophen-4′-yl)-2-morpholin-4-yl-chromen-4-one (103)

A mixture of xii (100 mg, 0.26 mmol), xiii (100 mg, 0.28 mmol), Pd(PPh₃)₄ (14.5 mg, 0.013 mmol) and potassium carbonate (106 mg, 0.768 mmol) was flushed with argon three times in vacuo, and dioxane (15 ml) was added. The reaction mixture was stirred at 85° C. for 12 hours. The mixture was diluted with DCM (50 ml) and the organic layer was washed successively with water (2×20 ml), brine (1×20 ml), dried (Na₂SO₄) and the solvent was evaporated in vacuo. The residual solid was purified by chromatography on silica, employing 5% methanol in DCM as eluent, to afford the title compound (103).

Rt=3.73 min; m/z=471.4; purity=95%

Biological Examples DNA-PK Inhibition

In order to assess the inhibitory action of the compounds against DNA-PK in vitro, the following assay was used to determine IC₅₀ values.

Mammalian DNA-PK (500 ng/ml) was isolated from HeLa cell nuclear extract (Gell, D. and Jackson S. P., Nucleic Acids Res. 27:3494-3502 (1999)) following chromatography utilising Q-sepharose, S-sepharose and Heparin agarose. DNA-PK (250 ng) activity was measured at 30° C., in a final volume of 40 μl, in buffer containing 25 mM Hepes, pH7.4, 12.5 mM MgCl₂, 50 mM KCl, 1 mM DTT, 10% Glycerol, 0.1% NP-40 and 1 mg of the substrate GST-p53N66 (the amino terminal 66 amino acid residues of human wild type p53 fused to glutathione S-transferase) in polypropylene 96 well plates. To the assay mix, varying concentrations of inhibitor (in DMSO at a final concentration of 1%) were added. After 10 minutes of incubation, ATP was added to give a final concentration of 50 μM along with a 30mer double stranded DNA oligonucleotide (final concentration of 0.5 ng/ml) to initiate the reaction. After 1 hour with shaking, 150 μl of phosphate buffered saline (PBS) was added to the reaction and 5 μl then transferred to a 96 well opaque white plate containing 45 μl of PBS per well where the GSTp53N66 substrate was allowed to bind to the wells for 1 hour. To detect the phosphorylation event on the serine 15 residue of p53 elicited by DNA-PK a p53 phosphoserine-15 antibody (Cell Signaling Technology) was used in a basic ELISA procedure. An anti-rabbit HRP conjugated secondary antibody (Pierce) was then employed in the ELISA before the addition of chemiluminescence reagent (NEN Renaissance) to detect the signal as measured by chemiluminescent counting via a TopCount NXT (Packard).

The enzyme activity for each compound is then calculated using the following equation:

${\%\mspace{14mu}{Inhibition}} = {100 - \left( \frac{\left( {{cpm}\mspace{14mu}{of}\mspace{14mu}{unknown}\text{-}{mean}{\mspace{11mu}\;}{negative}\mspace{14mu}{cpm}} \right) \times 100}{\left( {{mean}\mspace{14mu}{positive}\mspace{14mu}{cpm}\text{-}{mean}\mspace{14mu}{negative}\mspace{14mu}{cpm}} \right.} \right)}$

The results are discussed below as IC₅₀ values (the concentration at which 50% of the enzyme activity is inhibited). These are determined over a range of different concentrations, normally from 10 μM down to 0.01 μM. Such IC₅₀ values are used as comparative values to identify increased compound potencies.

Survival Enhancement Ratio

The Survival Enhancement Ratio (SER) is a ratio of the enhancement of cell kill elicited by the DNA-PK inhibitor after 2 Grays of irradiation compared to unirradiated control cells. DNA-PK inhibitors were used at a fixed concentration of 100 nM. Radiation was delivered by a Faxitron 43855D machine at a dose rate of 1 Gy pre minute The SER at 2 Gray irradiation was calculated from the formula:

${SER} = {\frac{{Cell}\mspace{14mu}{survival}\mspace{14mu}{in}\mspace{14mu}{presence}\mspace{14mu}{of}\mspace{11mu} D\; N\; A\text{-}P\; K\mspace{14mu}{inhibitor}}{{Cell}\mspace{14mu}{survival}\mspace{14mu}{of}\mspace{14mu}{control}\mspace{14mu}{cells}} \times \frac{{Cell}\mspace{14mu}{survival}\mspace{14mu}{after}\mspace{14mu} I\; R}{{Cell}\mspace{14mu}{survival}\mspace{14mu}{after}\mspace{14mu} I\; R\mspace{14mu}{in}\mspace{14mu}{presence}\mspace{14mu}{of}\mspace{14mu} D\; N\; A\text{-}P\; K\mspace{14mu}{inhibitor}}}$

The degree of cell killing was monitored by a standard clonogenic survival assay. Briefly, tissue culture treated 6-well plates were seeded with HeLa cells at an appropriate concentration to give 100-200 colonies per well and returned to the incubator in order to allow the cells to attach. Four hours later, compound or vehicle control was added to the cells. The cells were then incubated for 1 hour in the presence of inhibitor prior to irradiation at 2 Gray using a Faxitron 43855D cabinet X-ray machine. The cells were then incubated for a further 16 hours before the media was replaced with fresh media in the absence of DNA-PK inhibitor. After 8 days, colonies formed were fixed and stained with Giemsa (Sigma, Poole, UK) and scored using an automated colony counter (Oxford Optronics Ltd, Oxford, UK). The data was calculated as described above.

All the compounds showed activity in DNA-PK inhibition, exhibiting an IC₅₀ of less than about 100 nM.

Compounds which exhibited particular efficacy in DNA-PK inhibition, having an IC₅₀ of less than about 10 nM include 5, 18, 23, 24, 25, 26, 29, 32, 51, 53, 60, 81, 82, 83, 84, 85, 86, 88, 90, 91, 95.

All the compounds showed an SER of 1 or more. The following compounds had an SER of 2 or more: 1, 4, 13, 24, 26, 32, 34, 38, 40, 41, 48, 53, 56, 80, 82, 84, 88, 89. 

1. A compound of formula I:

and isomers, salts, solvates, chemically protected forms, and prodrugs thereof, wherein: R¹ and R² are independently selected from hydrogen, an optionally substituted C₁₋₇ alkyl group, C₃₋₂₀ heterocyclyl group, or C₅₋₂₀ aryl group, or may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms; Q is —NH—C(═O)— or —O—; Y is an optionally substituted C₁₋₅ alkylene group; X is SR³, wherein, R³ is selected from hydrogen, optionally substituted C₁₋₇ alkyl, C₅₋₂₀ aryl, or C₃₋₂₀ heterocyclyl groups; if Q is —O—, X is additionally selected from NR⁴R⁵ and —O(═O)—NR⁶R⁷, wherein R⁴ and R⁵ are independently selected from hydrogen, optionally substituted C₁₋₇ alkyl, C₅₋₂₀ aryl, or C₃₋₂₀ heterocyclyl groups, or R⁴ and R⁵ may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms, and R⁶ and R⁷ are independently selected from hydrogen, optionally substituted C₁₋₇ alkyl, C₅₋₂₀ aryl, or C₃₋₂₀ heterocyclyl groups, or R⁶ and R⁷ may together form, along with the nitrogen atom to which they are attached, an optionally substituted heterocyclic ring having from 4 to 8 ring atoms; and if Q is —NH—O(═O)—, —Y—X may additionally be selected from C₁₋₇ alkyl.
 2. A compound according to claim 1, wherein Q is —NH—C(═O)— or —O—.
 3. A compound according to claim 2, wherein X is NR⁴R⁵.
 4. A compound according to claim 3, wherein Y is an optionally substituted C₁₋₃ alkylene group.
 5. A compound according to claim 4, wherein Y is a C₁₋₂ alkylene group.
 6. A compound according to claim 1, wherein R⁴ and R⁵ are either independently selected from H and optionally substituted C₁₋₇ alkyl or R⁴ and R⁵ form, together with the nitrogen atom to which they are attached, an optionally substituted nitrogen containing heterocylic ring having from 4 to 8 ring atoms.
 7. A compound according to claim 1 of formula II:

wherein: R¹, R² and Q are as defined for formula I; n is 1 to 7; and R⁸ is selected from hydrogen, optionally substituted C₁₋₇ alkyl, optionally substituted C₅₋₂₀ aryl, and acyl.
 8. A compound according to claim 1, wherein R¹ and R² form, along with the nitrogen atom to which they are attached, a heterocyclic ring having from 4 to 8 atoms.
 9. A compound according to claim 8, wherein R¹ and R² form, along with the nitrogen atom to which they are attached, a heterocyclic ring having 6 ring atoms.
 10. A compound according to claim 8, wherein R¹ and R² form, along with the nitrogen atom to which they are attached, morpholino or thiomorpholino.
 11. A pharmaceutical composition comprising a compound according claim 1, and a pharmaceutically acceptable carrier or diluent. 